[2][3] He made his Major League debut on September 2, 1973, against the Atlanta Braves, starting the second game of a doubleheader.

[4] He pitched a complete game victory over the San Diego Padres on September 21 for his first career win while striking out 11.

D'Acquisto was named National League (NL) Rookie Pitcher of the Year in 1974 when he went 12–14 with a 3.77 ERA for the fifth-place Giants, but he missed most of the next season after elbow surgery.

D'Acquisto was traded (with Mike Caldwell and Dave Rader) to the St. Louis Cardinals for Willie Crawford, John Curtis and Vic Harris on October 20, 1976.

D'Acquisto did not pitch much with the Angels (6 appearances) during the strike-ridden year and was subsequently sent to the minor leagues in Salt Lake City, Utah.

In 1989, D'Acquisto pitched for the Bradenton Explorers and St. Lucie Legends of the Senior Professional Baseball Association, where he finished 5–4 with four saves.