Parker's family has lived on Chicago's South Side since before Jabari was born, and he was raised in the South Shore community area. Parker's father, Sonny, has served hundreds of Chicago metropolitan area children as youth foundation director since 1990. Parker discovered basketball in one of his father's many leagues, although his father has never coached one of his teams. He honed his basketball skills with his brother Christian on the basketball court at his local LDS Church meetinghouse in the Hyde Park community area in order to avoid the hazards of urban playgrounds. By second grade his basketball skills were superior to those of the fifth-graders he played with, and he competed in middle school leagues as a fifth grader. He credits his cousin Jay Parker who grew up with him for pushing him to be better going back to when Jabari was in third grade and Jay was in fifth grade. Sometimes, Jabari and Christian played basketball all through the night at the church. Jabari actually made the eighth-grade team as a fourth-grader, but could not play until fifth grade for insurance reasons. In fifth grade, he had five Division I scholarship offers as a 6-foot (1.83 m) guard. In sixth grade, when he stood at 6 feet 2 inches (1.88 m), he visited Simeon for a day and scrimmaged with Derrick Rose. Parker attended Robert A. Black Magnet Elementary and made headlines when he made Simeon Career Academy his high school choice, just like Rose, Nick Anderson, Ben Wilson, Bobby Simmons and Deon Thomas before him. Parker has two older sisters who had attended Simeon. However, he has claimed that the reason he chose Simeon was due to his perception of the likelihood that he could achieve team success on the basketball court (as measured in championships). During the summer after finishing middle school, he received a National Basketball Players Association Top 100 Camp invitation, which he accepted. By this time, he stood at 6 feet 4 inches (1.93 m).
Parker was the first freshman to start on the Simeon varsity team in school history. Over the course of the season, he contributed 19.3 points per game, 5.0 rebounds per game, and 3.0 assists per game, while his team won the IHSA Class 4A state championship with a 25–9 record. By the end of the season, he had received numerous scholarship offers, including those from Illinois, Kansas, DePaul, Pittsburgh, Northwestern, Florida, Washington, BYU and Oregon State as well as significant interest from Kentucky, Duke and North Carolina. He earned the ESPN HS 2010 Freshman of the Year. He was a MaxPreps.com second team 2009-10 Boys Basketball Freshman All-American Team selection.
As a sophomore, Parker helped his team spend much of the season ranked nationally in the top five. That season, he averaged 15.3 points and 5.9 rebounds per game, while his team won the IHSA Class 4A state championship with a 30–2 record. He earned second team All-State recognition from the Chicago Tribune, while the Chicago Sun-Times listed him as a Class 4A All-State first-team selection with Ryan Boatright, Tracy Abrams, David Sobolewski and Frank Kaminsky. The 12-man Illinois Basketball Coaches Association Class 3A/4A boys' all-state first team included these five and Wayne Blackshear, Johnny Hill, Mike Shaw, Nnanna Egwu, Sam Thompson, Anthony Davis and Mycheal Henry. He earned the ESPN HS 2011 Sophomore of the year. He was a MaxPreps.com first team 2010-11 Boys Basketball Sophomore All-American Team selection.
During his junior year preseason, Parker participated in the July 2011 LeBron James Skill Academy, and he was one of a handful of juniors invited to the August 5–7, 2011 5th annual Nike Global Challenge, where he earned tournament MVP honors.
During the season, Parker established the Simeon single-game scoring record with 40 points in 21 minutes of play to go along with 16 rebounds and 6 blocked shots against Perspectives High School. As a junior in high school, he received offers from Duke, Kansas, BYU, Kentucky, UNC, and others. On February 17, Parker and Simeon won the Public League championship by defeating Curie Metropolitan High School 53–49. Both the semifinals and finals were broadcast on ESPN3. Coaches Izzo, Krzyzewski, Matta and Weber as well as Mayor Emanuel and cadres of their assistants were among those in attendance to see this March 6 IHSA sectional semifinal against Young won by Simeon 52–42 in which Parker led the way with 18 points and 6 rebounds. In the days prior to the state final four, Parker stated that although Coach Weber had been fired, he remained interested in Illinois and other in-state schools such as DePaul and Northwestern. Parker had 15 points in the March 17 championship game 50–48 victory over the Sterling Brown-led Proviso East High School, resulting in a 33–1 junior year record for Simeon. The state semifinals and the finals were broadcast live on ESPN3. For the season, Parker averaged 19.5 points, 8.9 rebounds, 4.9 assists, 3.3 blocks and 1.4 steals per game or 20.4 points, 9.2 rebounds, 5.1 assists, 3.4 blocks and 1.5 steals per game, depending on the source, while shooting 55 percent from the field, 39 percent from 3-point range and 72 percent from the free-throw line. Following the season, he was featured in a May cover story in Sports Illustrated with the title "The Best High School Basketball Player Since LeBron James is...Jabari Parker But There's Something More Important To Him Than Instant NBA Stardom: His Faith". The story presented his humility and noted that he is conflicted on his decision to serve as an LDS missionary. Parker announced that he anticipated trimming his potential schools to a list of five by the end of the summer so that he could plan official visits.
For his efforts during his junior year, Parker earned several accolades. The Chicago Sun-Times named him to the Class 4A All-State first team along with Jahlil Okafor, Keith Carter, Darius Paul and Fred VanVleet. He was also a first team (unanimous) All-State selection by the Associated Press along with VanVleet, Carter, Taylor, and Malcolm Hill. The Chicago Tribune named him first team All-State along with Carter, Aaron Simpson, Taylor, and VanVleet. He was named the 2012 Illinois boys' basketball Gatorade Player of the Year. He became the first non-senior honoree in the 32-year history of Illinois Mr. Basketball, which is awarded by the Chicago Tribune in conjunction with the Illinois Basketball Coaches Association. On April 12, he was announced as the winner of the national boys' basketball Gatorade Player of the Year, which was presented to him by ex-NBA player Alonzo Mourning who greeted him at his school in a special assembly. Parker was the fourth junior to win the award (LeBron James, Greg Oden and Brandon Knight). Parker finished second to Muhammad in ESPN HS's Mr. Basketball USA voting. They were the only two players to appear on every ballot. However, Parker was selected as the ESPN HS National Junior of the Year and the MaxPreps.com National Junior of the Year. He was selected as a first team ESPN HS boys' high school basketball All-American along with Kyle Anderson, Marcus Smart, Shabazz Muhammad and Nerlens Noel by ESPN HS. He was also a first team All-USA selection by USA Today with the same four players. SLAM Magazine selected him to its first team along with Anderson, Muhammad, Noel and Isaiah Austin.
Parker entered the summer of 2012 as the consensus number one player in the country until he was sidelined with a foot injury, which caused him to miss some games during the 2012 FIBA Under-17 World Championship. Parker was one of ten USA Today preseason All-USA selections, and his team was ranked No. 1 preseason nationally by MaxPreps.com. On December 20, 2012, he chose to play for Duke.
Over the course of his senior season, Parker and Simeon played in six showcase games that required travel outside of the region. Three of the showcase games were broadcast nationally on one of the ESPN networks.
Parker led Simeon to its fourth consecutive IHSA class 4A state championship with a 58–40 victory over Stevenson High School, matching Manual High School's IHSA record of four consecutive IHSA basketball championships. In the process, Parker, who scored 20 points and had 8 rebounds, became the second player (Sergio McClain) in IHSA history to start for four consecutive state basketball champions. Simeon finished with a 30–3 record.
Several more accolades followed his senior year performance. USA Basketball selected Parker as a member of the 2013 USA Junior National Select Team for the April 20, 2013 Nike Hoop Summit at the Rose Garden. On February 12, Parker was recognized as a 2013 All-Public League first team selection by the Chicago Sun-Times. That same day, Parker was selected to play in the April 13 Jordan Brand Classic at the Barclays Center. On March 18, Parker earned the Morgan Wootten Male Player of the Year, which recognizes "the McDonald's All-American who demonstrates outstanding character, exhibits leadership and exemplifies the values of being a student-athlete in the classroom and the community". On March 21, Parker was named the Gatorade Illinois Boys Basketball Player of the Year, and on March 25, he repeated as Illinois Mr. Basketball. On April 9, he earned another National Player of the Year recognition, this time by MaxPreps.com. On April 17, he was a first team All-USA selection by USA Today, and on May 18, he was named a 2013 first-team Parade All-American.
During the McDonald's All-Star game played at the United Center in his hometown, Parker scored 10 points on 4-for-13 shooting and added 8 rebounds, 3 assists, 2 steals and 2 blocks, contributing to a 110–99 West victory. At the April 13 Jordan Brand Classic played at the Barclays Center, Parker was co-MVP along with Julius Randle. He had 16 points, 7 rebounds and 2 assists to help lead the West team to a 102–98 victory. At the April 20 Nike Hoops Summit held in Portland, Oregon, Parker had a team high 22 points and 7 rebounds as the U.S Junior National Select Team was defeated 112–98 by the World Select team.
Parker concluded his high school career as the fourth rated player in the class of 2013 according to Rivals, behind Wiggins, Randle, and Aaron Gordon.
During the summer prior to matriculating at Duke, Parker participated in the Nike sponsored Chi-League, a 9-weekend 10-team Chicago summer pro-am league, During this time, Parker was projected by the press as a true freshman starter for the 2013–14 Blue Devils, and he was assigned to wear number 1, a number only previously worn at Duke by Kyrie Irving. Preseason honors includes preseason All-American first team listings by Sporting News and USA Today, and being named the preseason ACC Rookie of the Year. Parker was also one of nine freshmen named to the 50-man Wooden Award preseason watchlist.
Parker debuted for Duke on November 8 with 22 points, 6 rebounds, 2 assists, and 1 block against Davidson—becoming Krzyzewski's fifth freshman to debut with 20 points and was part of Duke's first game with four 20-point scorers (along with Hood, Cook and Sulaimon) in school history. For his efforts, on November 11 Parker earned his first ACC Rookie of the Week recognition. On November 13, Parker earned his second Sports Illustrated cover as part of a four-version set of regional covers depicting college basketball's greatest rivalries on the College Basketball Preview Issue. On November 12 in the Champions Classic at his hometown United Center, Parker posted 27 points, 9 rebounds, 1 assist, 2 steals, and 1 block in a losing effort against Wiggins's Kansas Jayhawks. On January 18, Parker scored 23 against NC State, tying him with Gene Banks for most 20-point games by a Duke freshman. On January 25, Parker tallied 14 points, 3 steals and 14 rebounds against Florida State to help Mike Krzyzewski win his 900th game at Duke. On March 8, in the second Carolina–Duke rivalry game of the season, Parker had a career high 30 points. On March 10, he earned a record-tying (Kenny Anderson and Tyler Hansbrough) tenth ACC rookie of the week honor in the final week of the regular season.
In postseason play, Parker yielded a 20-point performance in the semifinals of the 2014 ACC Men's Basketball Tournament against NC State on March 15, which marked his 17th such effort and moved him into sole possession of second place on the ACC freshman list, ahead of Marbury. In the March 16 championship game against Virginia, Parker posted his 18th 20-point game, which was one short of Anderson's ACC freshman record. Parker and the team, ranked No. 3 in the Midwest region, ended the season in the first round of the NCAA Tournament with a loss to No. 14 Mercer. Parker set the Duke record for freshman scoring average (19.1) and became the first freshman to lead the team in both scoring and rebounding.
Parker has received much recognition for his freshman year performance. He was unanimously selected to both the Atlantic Coast Sports Media Association (ACSMA) All-ACC first team and the Coaches All-ACC Freshman Team. He was also selected to the Coaches All-ACC Basketball first team with the most points. Parker was voted the ACC Freshman of the Year receiving 72 of 77 votes and placed second for the ACC Player of the Year award, trailing Warren 48–25. Parker was a 2014 NCAA Men's Basketball All-American first-team selection by The Associated Press, The Sporting News, Sports Illustrated, NBC Sports, Bleacher Report, United States Basketball Writers Association (USBWA), National Association of Basketball Coaches (NABC), and USA Today. Parker was USBWA National Freshman of the Year and named to the 2013 Freshman All-American. He was selected to the first team All-ACC Tournament team. Parker also earned John R. Wooden Award All-American Team recognition.
On April 17, Parker declared for the 2014 NBA draft in an exclusive autobiographical story in Sports Illustrated. According to Bleacher Report, he signed with sports agent Rich Paul, who is LeBron James's agent, but other sources, such as SLAM Magazine, suggest that he signed with BJ Armstrong, who is Derrick Rose's agent. Parker (along with other top prospects Andrew Wiggins and Joel Embiid) decided to decline the invitation to participate in the NBA Draft Combine. On June 26, Parker was selected no. 2 overall by the Milwaukee Bucks. Just prior to the draft, Parker became the second member of the 2014 draft class to sign a shoe contract when he signed an endorsement deal with the Jordan Brand.
On July 9, 2014, Parker signed with the Bucks and joined them for the 2014 NBA Summer League. In the 2014–15 NBA.com Rookie Survey at the annual Rookie Photo Shoot on August 6, Parker was named by his peers as both the most likely to be Rookie of the Year and the most likely to have the best NBA career.
On October 29, 2014, Parker made his NBA debut in the Bucks' season opener against the Charlotte Hornets. In just under 37 minutes of action as a starter, he recorded 8 points, 4 rebounds, 1 assist, and 1 steal in a 108–106 overtime loss. Two nights later in his first home game, he posted a double-double with 11 points and 10 rebounds against the Philadelphia 76ers. On November 19, he posted a season-high 23 points in a triple-overtime win over the Brooklyn Nets. Parker was selected as the October/November Eastern Conference Rookie of the Month. On December 15, Parker suffered a season-ending injury by tearing his anterior cruciate ligament (ACL) against the Phoenix Suns.
Parker's injury extended into the beginning of the 2015–16 NBA season. He returned to action on November 4 against the Philadelphia 76ers in the fifth game of the season for the Bucks but struggled, posting just two points in 16 minutes as a starter. As he ramped up his activity, he was rested on the second of back-to-back games. Nonetheless, after five games, he endured a sprain in his talonavicular joint in the right mid-foot causing him to be expected to miss several games. He only missed one game. The following week, he began to come off the bench while O. J. Mayo took his starting spot. On December 12, Parker had a 19-point, 7-rebound, 2-steal performance against the Golden State Warriors to help end their 24-game win streak. On January 27, 2016, he was named to the 2016 NBA All-Star Game weekend Rising Stars Challenge lineup. On February 19, he tied his career high with 23 points in a loss to the Charlotte Hornets. He surpassed that total the following night, recording career highs of 28 points and 13 rebounds in a 117–109 double-overtime win over the Atlanta Hawks. On February 29, Parker set a new career high with 36 points in a 128–121 Bucks victory over the Houston Rockets.
On February 9, 2017, Parker was ruled out for the rest of the 2016–17 season after an MRI revealed a torn anterior cruciate ligament (ACL) in his left knee. The recovery and rehabilitation period is estimated at 12 months. It was his second ACL tear in the same knee, the first having occurred in December 2014.
In October 2010, Parker was among the 18 players who participated in the 2011–12 USA Developmental National Team mini-camp giving him an automatic invitation to the June 10–18, 2011 tryouts for FIBA U16 competition at the United States Olympic Training Center in Colorado Springs, Colorado. Parker was one of four Chicago products to emerge from the 27-man tryouts as part of the 12-man team. He was MVP of the 2011 FIBA Americas U16 Championship, where Team USA won a gold medal. This qualified the United States for the 2012 FIBA U17 World Championship. The team, which was coached by Don Showalter of Mid-Prairie High School, scored over 100 points in each outing. Parker set the USA U16 single-game scoring record of 27 points. In December 2011, he was named USA Basketball's Male Athlete of the Year based on his FIBA Americas performance, which made him the youngest winner ever. While on the stage to accept the award from Chicago Mayor Rahm Emanuel, he claims that he told the mayor "I hope they don't boo me."
He was selected for the USA team that competed in the 2012 FIBA Under-17 World Championship in Kaunas, Lithuania from June 29 – July 8, 2012 along with Simeon teammate Kendrick Nunn and Whitney Young rival Okafor. The team won the gold medal, although Parker missed some games, including the semifinal, with an ankle injury.
Parker was frequently compared to Derrick Rose in high school. According to Chicago Sun-Times writer Michael O'Brien, as of November 2011, Rose had a 3–0 advantage in defining moments: "the back-to-back dunks against Washington in the city championship at the United Center, the game-winning shot in overtime to give Simeon the state championship against Peoria Richwoods and the dismantling of Oak Hill, the top-ranked team in the country." Rose's game against the Oak Hill team with Brandon Jennings, Nolan Smith and Alex Legion on ESPN is described as Rose's national introduction. Although there are comparisons to Rose, his game is most often compared to Grant Hill and Paul Pierce. Dime Magazine describes him as "Grant Hill with a jump shot". Parker claims to model his game after Paul Pierce and Carmelo Anthony. He hopes to be regarded as the best high school basketball player in the history of the city of Chicago and has stated that "being compared to Derrick also drives me. I know if I get better than him or break the records he broke I could be one of the best players to come out of Chicago. I look forward to being one of those players."
Because of the title of the Sports Illustrated story that compared Parker to LeBron James, Mike DeCourcy of Sporting News stated that "Jabari Parker is, rather, the best [high school basketball player] since Greg Oden." In addition, Parker was considered to have a much less developed physique than James at the same stage of development. CBS Sports' Jeff Borzello also contested the proclamation, pointing out that since James's 2003 class both Dwight Howard (2004) and Oden (2006) were consensus top players in their classes and that Parker might not be any better than the most recent consensus, Oden. In addition, CBS noted that Parker "might not even be the best high school basketball player in the country, given the development of class of 2014's Andrew Wiggins." Chicago Tribune writer Mike Helfgot described the Sports Illustrated comparison as "incredibly irresponsible journalism", noting he had once worked for the Star-Ledger when it described Derrick Caracter as the next James.
Following his four consecutive championships with Simeon, Parker (and Chicago's Simeon) were compared to McClain (and Peoria's Manual). Peoria's Journal Star emphasized that McClain was 32–0 as a starter in IHSA play because in the 1994–97 time period the IHSA was only divided into two classes. Thus, Manual had to wade through an 8-round tournament instead of the 7-round modern 4-class format. However, Simeon won 6 of its 7 games in its final championship by more than 10 points, while Manual only won 3 of its 8 by such a margin. In the postgame press conference, Simeon Coach Smith emphasized that his team had to endure the pressure of playing a national schedule that included games against elite teams in distant venues. Note, that with the 4-class system rather than the 2-class system of the past, the 2013 Class 3A IHSA champion was CPL runner-up Morgan Park, who split 2 neutral court 2013 games with Simeon. As noted above, Rose-era Simeon teams only won 2 championships in the 2-class era. Adding Parker's 55-11 start to a 33–1 junior year and a 30–3 senior season gives him a 118–15 legacy compared to Rose's 120–12.
Parker is of Tongan and African American descent. His parents are Folola "Lola" Finau-Parker and Sonny Parker. His father, Sonny, a Chicago native, played for the Texas A&M Aggies before becoming a 1976 NBA Draft first round selection (17th overall) by the Golden State Warriors. He played in the NBA for six seasons. Sonny was an NBA teammate of former Washington Huskies men's basketball head coach Lorenzo Romar. In 2013, he developed a kidney disease that requires dialysis, making it difficult for him to attend Jabari's games. His mother, Lola, a Polynesian native of Tonga, is a member of The Church of Jesus Christ of Latter-day Saints (LDS Church) and emigrated to Salt Lake City at age three. Her grandfather was the second Tongan baptized by LDS missionaries. Several of Lola's cousins are National Football League athletes, including Harvey Unga, Haloti Ngata and Tony Moeaki, and one of her first cousins once removed, Tony Finau, made his PGA Tour debut in October 2014. His parents met at a mall when she was a student at Brigham Young University and he was playing for the Warriors. After helping him find a dress shirt, Sonny left her tickets to his game. After he retired and she served her mission, they married and settled in Chicago. The family lives in the South Shore community area where his parents settled after marrying and has turned down two movie offers.
Parker has six siblings. His older brothers are named Darryl and Christian, while his older sisters are named Iman and Tilah. Darryl lettered two years for the Oregon Ducks basketball team, starting for the team in the 1995 NCAA Men's Division I Basketball Tournament. Christian played basketball for Brigham Young University–Hawaii.
Jabari grew up (and remains) an active member of the Church of Jesus Christ of Latter-day Saints. While attending Simeon Career Academy, Parker attended LDS Seminary two mornings a week, according to ESPN, and three days a week, according to The New York Times, Sports Illustrated and Chicago Sun-Times. At the time of his sixteenth birthday, he became a LDS priest (as is customary in his faith). He has both performed baptisms and administered the weekly sacrament. In addition, he regularly traveled with his bishop during his monthly visitations to comfort the sick, the poor and the elderly.
Parker worked out with basketball trainer Tim Grover. Jabari prefers individual training sessions with his brother Darryl instead of playing pick-up games. Following his sophomore year, ESPN reported that he had a 3.4 grade point average. By the end of the first semester of his junior year, The New York Times reported his GPA was 3.7. By April of his junior year, his GPA was 3.63, ranking 18th in his class of 377 and his extracurricular activities includes service as the principal-appointed president of student representatives to the local school council, a youth basketball instructor, and a volunteer for Operation PUSH, The Salvation Army, and the New Beginnings Church. In high school, he was known for carrying a backpack filled with basketball equipment, along with an iPod, and a copy of the Book of Mormon.