He was a baseball All-Star in 1977, 1979, 1980, 1981, 1985, 1986, and 1990. In the 1979 All-Star Game, Parker showcased his defensive ability and powerful arm by throwing out Jim Rice at third base and Angels catcher Brian Downing at home. Parker also contributed an RBI on a sacrifice fly and was named the game's MVP.
Parker grew up in Cincinnati near Crosley Field, where he learned to play baseball on the stadium's parking lots. His father, Dick Parker, was a shipping clerk in a foundry. Dave Parker attended Courter Tech High School. He has said his favorite sport was football, and he starred at tailback but injured a knee in a game during his senior year and gave up the game. Also a baseball star, one of his fondest memories is playing at Western Hills High School (alma mater of Pete Rose), where he hit a home run that landed on the roof of a Frisch's restaurant.
In the early 1970s, as a member of the Pirates AAA minor league ball team Charleston (WV) Charlies, Parker hit a home run that landed on a coal car on a passing train and the ball was later picked up in Columbus, Ohio. He began his major league career on July 12, 1973 with the Pittsburgh Pirates, for whom he played from 1973 to 1983.
At the 1977 MLB All-Star Game he became the only player in history to have worn batting helmets from two different teams—neither of them his own—in the same game, wearing a San Diego Padres helmet early on before swapping it out for a Cincinnati Reds one.
In 1977, he was National League batting champion, a feat he repeated in 1978 when he was named the National League's MVP. This was in spite of a collision at home plate with John Stearns during a game against the Mets on June 30, 1978, in which Parker fractured his jaw and cheekbone; he wore a specially constructed facemask in order to minimize his time away from the lineup. The Pirates rewarded him with baseball's first million-dollar-per-year contract. The following year, he was an instrumental part of the Pirates' World Series championship team.
During a game in 1979, a powerful hit he made to right field was very difficult to throw into the infield, because he had "knocked the cover off the ball." One of the seams on the ball ruptured, making nearly half of the cover come loose.
Pittsburgh fans angered by his million-dollar contract threw "nuts and bolts and bullets and batteries" at him, as pitcher Kent Tekulve stated; a typo in a news story made it appear that they threw car batteries.
In 1981, at a point in his career when it looked as if he would one day rank among the game's all-time greats, Lawrence Ritter and Donald Honig included him in their book The 100 Greatest Baseball Players of All Time. The authors, noting that Parker had succeeded Roberto Clemente at the position, wrote, "Someone must have a fondness for right field in Pittsburgh."
Parker took after his Pirates teammate Willie Stargell in warming up in the on-deck circle with a sledgehammer (when most batters would use a simple lead-weighted bat).
In the early 1980s, however, Parker's hitting suffered due to injuries, weight problems, and his increasing cocaine use. He became one of the central figures in a drug scandal that spread through the major leagues.
At the end of the 1983 season, Parker became a free agent and signed with the Cincinnati Reds. In Cincinnati, his hometown, he returned to the form that made him an All-Star in Pittsburgh. In 1985, he enjoyed his best season since he won the 1978 MVP with a .312 batting average, 34 home runs, and 125 RBI. Parker finished second in 1985 MVP voting to Willie McGee.
Following the season, Parker was among several players who testified against a dealer in the Pittsburgh drug trials. Named as "regular users", Parker and six other players were suspended for the following season. The sentences were commuted, however, in exchange for donating ten percent of their base salaries to drug-related community service, submitting to random drug testing, and contributing 100 hours of drug-related community service.
After the 1987 season, Cincinnati traded Parker to the Oakland Athletics for José Rijo and Tim Birtsas. In Oakland, Parker was able to extend his career by spending most of his time as a designated hitter. Although injuries and age caught up to him to a degree – he hit just .257 with 12 homers in 377 at-bats in 1988 and .264 with 22 homers in 553 at-bats in 1989 – his veteran leadership was a significant factor in the A's consecutive World Series appearances.
Parker signed with the Milwaukee Brewers for the 1990 season and had a solid year as the Brewers' DH with a .289 average and 21 home runs in 610 at-bats. Milwaukee opted for youth, however, at the end of the year and traded the aging Parker to the Angels for Dante Bichette.
Parker's last season was 1991. He played for the California Angels until late in the season when he was released. The Toronto Blue Jays then signed him as insurance for the pennant race, and Parker hit .333 in limited action. Since he was acquired too late in the season, however, he did not qualify for inclusion on the post-season roster and thus was unable to play in the American League Championship Series against the Minnesota Twins, which the Blue Jays lost in five games. Parker retired at the end of the season.
Parker has served as a first-base coach for the Anaheim Angels, a batting coach for the St. Louis Cardinals in 1998, and a special hitting instructor for Pittsburgh. He owned several Popeye's Chicken franchises in Cincinnati until selling his interest in them in 2012 after 25 years.
Parker never got more than 24% of votes on Hall of Fame ballots, and his 15-year Baseball Writers' Association of America eligibility was exhausted on the 2011 ballot. He can be now considered for the Veterans Committee Expansion from 2014. Along with Keith Hernandez and (until 2017) Tim Raines, Parker's involvement with the Pittsburgh drug trials has been the most likely cause of his not being voted into the Hall of Fame, serving as a precursor to those listed on the Mitchell Report not being voted into the Hall of Fame due to steroid abuse.
Parker has had both of his knees replaced due to injuries from his playing career. In 2013, he confirmed to the Pittsburgh Tribune-Review that he had been diagnosed with Parkinson's disease.
Parker has six children. He currently resides in Loveland, Ohio, near Cincinnati, with his wife, Kellye.
Parker was elected to the Reds Hall of Fame Class of 2014, which also included fellow Cincinnati natives Ron Oester and Ken Griffey Jr. In 2012, he was inducted into the Cincinnati Public Schools Athletic Hall of Fame.