Aquino, a right handed pitcher, was originally signed by the Toronto Blue Jays as an undrafted free agent in 1981, going 1-1 with a 6.35 ERA for the team in a short call-up in 1986.
Traded by the Jays to the Kansas City Royals for Juan Beniquez in 1987, he would make his next Major League appearance in 1988. For parts of five seasons, Aquino was a long and middle reliever, as well as a spot starter for the Royals. In 114 career games for the team, he posted a 22-19 record with a 3.54 ERA. Aquino also appears on the Royals list, coming in at number 80.
The Florida Marlins purchased Aquino's contract from Kansas City just prior to their inaugural 1993 season, making Aquino an original Marlin. He would pitch for two seasons with the team.
In 1993, Aquino compiled a 6-8 record and a 3.42 ERA. He pitched in 38 games, 13 of them starts. In 110.2 innings pitched, he struck out 67.
1994 saw Aquino allow an impressive 6.9 hits per nine innings pitched, posting a 2-1 record and a 3.73 ERA in 50.2 innings.
For his Marlins career, Aquino compiled an 8-9 record over 67 games. He allowed 8.6 hits per nine innings and posted an ERA of 3.51.
Aquino split 1995 between the Montreal Expos and the San Francisco Giants. Released by the Giants before seasons end, Aquino was signed by the Boston Red Sox but never appeared in any games for the team, being released just 18 days later.