King averaged 25.8 points per game in three years as a starter at the University of Tennessee and led NCAA Division I schools with a .622 field goal percentage as a sophomore. He left school after his junior year to enter the 1977 NBA draft.
He was chosen in the second round by the New Jersey Nets and averaged 24.2 points per game to make the all-rookie team. A 6-foot-7, 205-pound forward, King was traded to the Utah Jazz in 1979 but missed most of the season with a knee injury and was sent to the Golden State Warriors.
King was named comeback player of the year after averaging 21.9 points a game in 1980-81. Golden State traded him to the New York Knicks in 1982. With New York, King led the NBA in scoring with 32.9 points a game in 1984-85.
Because of a career-threatening knee injury, King missed all of the 1985-86 season and played in only 6 games in 1986-87. He was released by the Knicks and signed with the Washington Bullets in 1987.
The recurring knee problem forced him out for all of the 1991-92 season, but King returned to appear in 32 games with New Jersey in 1992-93. In 874 regular season games, he scored 19,655 points, an average of 22.5 per game, and he added 687 points in 28 playoff games, a 24.5 average.