After playing youth football for six years with Palmdale Falcons Youth Football (California), Moore attended William S. Hart High School in Newhall, California. He has Mexican American ancestry.
As a junior, Moore lettered in football while playing as a safety, earning All-CIF acclaim with 80 tackles and 10 interceptions on the season.
Moore lettered again during his senior year playing as Hart High School's starting quarterback. Moore led his team to a 13–0 record, culminating in a 42–13 win over Valencia in the CIF-Southern Section Division III title game. In the sectional, division title game, Moore completed 14 of 18 passes for 277 yards and four touchdowns and ran 15 times for 95 yards and one score. On the year, he completed 234 of 353 (66.3%) passes for 3,334 yards and 33 touchdowns and ran for 415 yards and seven scores. Moore was named the CIF-SS Division III Offensive Player of the Year. He was named First-team All-State and First-team All-CIF SS. He was selected to play in the 2002 North-South Shrine All-Star game.
Moore ended his senior season as one of the top-rated quarterbacks in the nation. He was ranked No. 8 by Scout.com and No. 11 by Rivals.com. SuperPrep rated him as the No. 8 quarterback in the nation and named him the FarWest Offensive Player of the Year. Max Emfinger named him to his All-America team and ranked him as a four-star prospect and the No. 17 quarterback prospect. PacWest Football rated Moore a four-star rating and rated him the No. 6 quarterback in the West and No. 9 in the nation. PrepStar named Moore to the All-American team and rated him the No. 5 quarterback in the West. He was named member of the Tacoma News Tribune Western 100, the Las Vegas Sun Super 11 second team, the Los Angeles Times All-Star Team, and the First-team L.A. Times All-San Fernando Valley, which selected him as the region Player of the Year.
Moore lettered twice in baseball playing shortstop and third base.
Moore began his college football career at UCLA. He was slated to redshirt, but was pressed into duty due to injuries to Cory Paus and Drew Olson against Cal. He appeared in six games as a true freshman, becoming the first Bruin true-freshman quarterback to start since Cade McNown. The Bruins defeated Stanford in Moore’s debut, making him the first true-freshman QB in his first game to lead UCLA to victory. He led the team to seven scoring drives against the Cardinal. He saw action against Arizona, USC, Washington State, and New Mexico in the Las Vegas Bowl as a reserve. Moore was 7 for 11 for 64 yards and one touchdown in the annual rivalry game vs. USC. For the season he completed 33 of 62 passes for 412 yards, two touchdowns and no interceptions.
Moore started four of the eight games he appeared in at UCLA. He threw for 555 yards, two touchdowns, and six interceptions as a sophomore, completing 52 of 103 passes. He started the season opener against Colorado, but suffered a leg injury that sidelined him for the next three games. He had difficulty regaining the starting job with just eight pass attempts over the next three games. He moved back in front of Olson on the depth chart for the Oct. 26 game at the Rose Bowl against Arizona State, passing for 190 yards and a touchdown in UCLA’s 20–13 win. He also started the team’s next two games against Stanford and Washington State. At the end of the season, Moore transferred from UCLA. (LA Times, Dec. 5, 2003).
Moore did not play in 2004 while attending the College of the Canyons in Santa Clarita, California. Although he had not played baseball since high school, he was selected in the 22nd round of the 2004 MLB draft by the Los Angeles Angels after scouts saw him play in a Southern California semi-pro baseball league and invited him to private workouts with the team.
Although he also strongly considered Colorado State, Moore enrolled at Oregon State in January 2005 and participated in spring training with the team. Head coach Mike Riley announced him as the leader on the depth chart entering the 2005 season. He finished the season with 2,711 yards passing, the ninth-highest total for a single season at OSU. His .594 completion percentage was third among the 20-best single season yardage performances in school history. Moore injured his right knee in the second quarter of the 10th game of the season against Stanford and missed the remainder of the year. His 271.1 yards passing per game was second in the Pac-10, trailing only USC's Matt Leinart (293.5). Making yet another record-breaking debut, he threw for 367 yards in the season opener against Portland State, the most ever by a Beaver quarterback in his first start. Moore threw for a career-high 436 yards against Arizona, had 317 yards at Louisville, and 311 against Arizona State. He hit Mike Hass on a 63-yard touchdown strike against Washington State that gave OSU the lead 37–33 after the team trailed 30–13 late in the second quarter. He also had two 58-yard passes—one to Anthony Wheat-Brown in the team’s upset of No. 18 California in Berkeley and the other one week later (again to Hass) in his return to the Rose Bowl.
Moore started all 14 games for the Beavers and was an All-Pac-10 honorable mention leading the Beavers to a 10-win season capped off by a Sun Bowl victory against Mizzou. After a 2–3 start, Moore and coach Mike Riley received a great deal of criticism from fans. Both found redemption after winning the next 8 of 9 games. This streak included a win over #3 ranked USC and a Civil War win at home. On the season, Moore completed 229 of 378 passes for 3,022 yards and 18 touchdowns with seven interceptions. He set an Oregon State record for the most consecutive pass attempts without an interception with 183 before having that streak end in the Sun Bowl. He was named MVP of the Sun Bowl after throwing for 356 yards and four touchdowns and rushing for one touchdown. The 4 passing TDs were a Sun Bowl record. It was the second-highest scoring game in the Sun Bowl's 73-year history. He was 5-for-7 for 55 yards on the winning drive, setting up a 2-point conversion to put the Beavers up 39–38 with 22 seconds left to play.
Moore was not selected in the 2007 NFL Draft, but he was suited by the Dallas Cowboys and the Carolina Panthers, among other teams. Eventually, Moore signed as an undrafted free agent with the Dallas Cowboys. On signing with Dallas, Moore stated, "They had two quarterbacks on the roster; it was the Cowboys," adding "seemed like an easy choice to me at the time."
During the preseason, Moore completed 21 of 29 pass attempts for 182 yards, one touchdown, and no interceptions, while also logging a 100.1 quarterback rating. On September 1, the Cowboys waived Moore during their final preseason cuts. The Cowboys intended to sign Moore to their practice squad had he passed through waivers. However, the following day, he was claimed off waivers by the Carolina Panthers.
After being signed by the Panthers, Moore was listed as the third-string quarterback behind veterans Jake Delhomme and David Carr. Delhomme suffered a strained right elbow injury, early in the season, during a game against the Atlanta Falcons. Moore saw his first regular season action on October 7, 2007, against the New Orleans Saints, during the Panthers' 5th game of the season. Near the end of the first quarter, Moore entered the game after Carr suffered a back injury, due to a sack. Moore's first NFL completion was a 43-yard pass to Keary Colbert; his playing time was brief as Carr returned to the field for the game's second half. The following day, Delhomme determined it would best to undergo season-ending ligament-replacement surgery for his elbow injury. As a result of Delhomme's season-ending surgery and Carr's back injury, the Panthers signed veteran quarterback Vinny Testaverde to their roster.
Moore later briefly relieved Carr towards the end of a Week 9 game against the Tennessee Titans. Moore also entered the Panthers' Week 12 loss to the Saints, after Carr's ineffective performance. A balky back kept Testaverde from the starting this game, and Panthers head coach John Fox stated that if healthy enough, Testaverde would start the next game over both Carr and Moore.
After six brief appearances during the season, Moore started his first NFL game on December 16, 2007, against the Seattle Seahawks; Testaverde was ruled unable to play, because of "general soreness." He led the Panthers to victory against the Seahawks while completing 19 of 27 passes for 208 yards without a turnover. The following week, the Panthers suffered a loss against the Cowboys, while Moore had 15 completions on 28 pass attempts for 182 yards, a touchdown, and an interception. During the game, Steve Smith hauled in Moore's first NFL touchdown pass. The Panthers ended the season with a road win against the Tampa Bay Buccaneers, in which Moore completed 15 of 24 pass attempts for 174 yards, two touchdowns, and an interception. After these performances, Moore was named the NFL Offensive Rookie of the Month for December.
Moore played in all four 2008 preseason games for the Panthers; during the final preseason game against the Pittsburgh Steelers, Moore injured his leg. Moore was cleared to practice as two x-rays and an MRI revealed no broken bones. However, during a practice, Moore injured his leg, and an x-ray revealed a broken fibula. Panthers general manager Marty Hurney initially stated Moore would not be placed on injured reserve. Despite this, Moore was sidelined the entire 2008 season, and even spent the last 12 weeks of the season listed as inactive.
Moore saw his first action of the 2009 season when backup quarterback Josh McCown was injured during the Panthers Week 1 loss to the Eagles. Moore finished with 6 of 11 passes for 63 yards, 1 touchdown and 1 interception. Moore also played briefly against the Arizona Cardinals, attempting one pass which was incomplete.
After starter Jake Delhomme broke his finger in a week 12 loss to the New York Jets, Moore started against Tampa Bay on December 6, 2009, the following week. He completed 14 of 20 passes for 161 yards and an interception, en route to a 16–6 Panthers victory. The following week, he completed 15 of 30 passes for 197 yards and a touchdown in a 20–10 loss to the New England Patriots.
On December 20 (in his 6th start) Moore had the best game of his career when he led the Panthers to a 26–7 upset victory over the Minnesota Vikings. In the victory he completed 21 of 33 passes for 299 yards, 3 touchdowns, and 0 interceptions, and improved to a career 4–2 as a starter. He drew praise from head coach John Fox and top receiver Steve Smith, who caught 9 passes from Moore for 157 yards and a score.
On December 27 Moore completed 15 passes on 20 attempts for 171 yards, and for the second week in a row, three touchdowns and no interceptions, as Carolina beat the New York Giants 41–9. Moore had a career-high 139.8 passer rating. The victory came during the final game to be played in Giants Stadium and essentially eliminated the Giants from the playoffs. The Giants' home loss was their worst since 1998. Moore again drew praise from analysts, including Tony Dungy who said that Moore "looked liked a pro-bowler".
Moore started the last game of the Panther's season on January 3, 2010, as the Panthers beat the New Orleans Saints 23–10. The Saints, who were the No. 1 seed in the NFC, were handed their third loss of the season as they rested most of their starters. The game was the coldest home game in team history for the Panthers. Moore completed 14 passes on 23 attempts for 162 yards and a touchdown. The win improved the Panthers to .500 with an 8–8 record (4–1 while starting Moore) to finish the season.
In his five games as a starter for the 2009 season, Moore threw eight touchdown passes with one interception. The strong finish by Moore and the Panthers, combined with earlier poor play by Jake Delhomme, led to speculation that Moore would challenge, if not replace, Jake Delhomme's role as the starting quarterback for the 2010 season despite Delhomme's large contract. This turned out be the case as Delhomme was cut from the Panthers on March 4, 2010.
Moore was declared the starter for the 2010 season after Delhomme's release. Despite this, the Carolina Panthers drafted rookie Jimmy Clausen with their second pick (48th overall) of the 2010 NFL draft. Though Moore had clearly established himself as the Panther's number one quarterback, he faced pressure for the starting job from Clausen, possibly resulting in his poor play throughout the rest of the season. Moore suffered a concussion during the season opener at the New York Giants, and he was benched the following week in a loss against the Tampa Bay Buccaneers following poor play. On September 20, 2010, Moore was removed as the Panthers starting quarterback in favor of rookie Jimmy Clausen, after throwing 4 interceptions in the first two games.
After sitting out for 3 straight games, Moore was again declared the Panthers starting quarterback on October 18, 2010, following poor play by Clausen. In his first game back as a starter against the San Francisco 49ers, Moore completed 28 passes on 41 attempts for 308 yards, two touchdowns and one interception, setting career highs in yards and completions.
In a week 9 loss to the New Orleans Saints, Moore injured his shoulder after a hit from Sedrick Ellis. He was placed on injured reserve by the Panthers, ending his season.
Moore was signed by the Dolphins on July 28, 2011 to back up Chad Henne. He switched numbers, from 3 to 8. On October 2, 2011 Moore entered the game against the Chargers in the 1st quarter after Henne went down with a shoulder injury. He completed 17 of 26 passes for 167 yards and an interception, compiling a 67.3 quarterback rating. On November 6 he became the first Miami quarterback since Chad Pennington in 2008 to throw three touchdown passes in a game, in their 31–3 win over the Kansas City Chiefs. He repeated that feat in week 11, blowing out the Bills 35–8, and had the highest QB rating of the week. Following the season, he was announced as the Dolphins' 2011 season MVP.
During the offseason, Moore was battling for the starting QB role against newly drafted Ryan Tannehill and newly signed David Garrard. Moore became the second quarterback. On November 28, 2012, in a Week 8 game against the New York Jets, Moore went in for Tannehill after he left the game with injuries to his left knee and thigh. Moore went 11 for 19 on his passes with a touchdown to lead a 30–9 victory over the Jets.
On March 8, 2013, Moore re-signed with the Dolphins, agreeing on a two-year deal to remain a backup for Tannehill.
On March 15, 2016, Moore re-signed with the Dolphins, agreeing on a two-year deal worth $3.5 million to remain a backup for Tannehill. On December 11, 2016, during a Week 14 game against the Arizona Cardinals, Moore saw his first action as quarterback for the season. He replaced Tannehill in the 4th quarter, after Tannehill was injured on a low hit by Cardinals defensive end Calais Campbell. The injury would later be confirmed as a sprained left MCL and ACL. Moore led a game-winning field goal drive, highlighted by Moore's 29-yard pass to wide receiver Kenny Stills deep in the final quarter to put the Dolphins on the 3-yard line. After a couple of plays, Dolphins kicker Andrew Franks kicked a field goal from the 21 yard line in heavy rain to win the game 26–23, keeping the Dolphins' playoff hopes alive. He started the next game against the New York Jets, completing 12 of 18 passes for 236 yards and a career-high four touchdowns with one interception as the Dolphins beats the Jets by a score of 34-13, improving their record to 9-5 and clinching their first winning season since 2008. It was Moore's first start since 2011. With his performance, Moore was named AFC Offensive Player of the Week.
Moore was announced the starting quarterback for the Dolphins against the Pittsburgh Steelers in the wildcard round of the 2017 National Football League playoffs as Tannehill did not appear to be fully recovered. This was Moore's first playoff game. The Dolphins would lose 30-12 to the Steelers in Pittsburgh.Regular season