Sundvold's best year as a professional came during the 1986–87 season as a member of the Spurs, appearing in 76 games and averaging 11.2 ppg. Selected by the Miami Heat in the 1988 NBA Expansion Draft, Sundvold played more of a bench role but still led the NBA in three point shooting percentage in 1989, hitting more than 50-percent of his attempts.
Sundvold's peak performance as a professional occurred during the 1986–87 season while playing for the Spurs, averaging 11.2 points per game and appearing in 76 games. He was drafted by the Miami Heat in the 1988 NBA Expansion Draft and continued to be a key player despite his role being more of a bench player.  He led the NBA in three-point shooting percentage in 1989, making over 50 percent of his attempts.