Drafted by the Phillies in the 5th round in 1988.  Mickey's first major league game was September 1, 1990.  On September 20, 1992: Phillies 2B Mickey Morandini became the 9th player in history to turn an unassisted triple play in Philadelphia's 13 inning 3–2 loss to the Pirates.  With runners on 1st and 2nd in the 6th inning, Morandini caught Jeff King's line drive, stepped on 2nd to double up Andy Van Slyke, and tagged out Barry Bonds, who was running from 1st.

A pivotal player on the Phillies 1993 National League championship.  In 1995 Mickey was named to the All-Star team and on June 24, 1995 Mickey Morandini stroked five hits to lead Philadelphia to a 10-9 win over the Cardinals.  He got three singles and two doubles, drove home three runs, and scored a pair to help the Phillies maintain their five game lead over Atlanta in the National League East.

Mickey possessed extra-base power, finishing seventh in the league in doubles in 1995 and 1997, and among the National League leaders in triples from 1992 to 1995.  Mickey possessed good speed with 123 career stolen bases, and had a career fielding percentage of .989 at second base.

Mickey finished his Major League Career on October 1, 2000.