At 20 years of age, Witt made his major league debut with the California Angels in 1981. Standing 6 feet, 7 inches tall and possessing a great curveball as well as a good fastball, Witt's breakout season came in 1984, when he went 15–11 for the Angels. On July 23 of that year, he struck out 16 Seattle Mariners during a complete game five-hitter; but the highlight of the year came on the final day of the season, September 30, when he pitched the 11th perfect game in baseball history against the Texas Rangers at Arlington Stadium. He struck out 10 and needed just 94 pitches to complete the gem. Witt's perfect game is, to date, one of five no-hitters pitched on the final day of a Major League Baseball regular season.