MacLeod made his professional debut during the 1989-90 season with the Kalamazoo Wings, the Minnesota farm team at the time. He impressed instantly scoring 47 points in his first season as a pro on nine goals and 38 assists. Pat would spend the majority of the 1990-91 season with the Wings as well, but did appear in one game for the Minnesota North Stars, collecting 1 assist.
Following the season, MacLeod was selected by the San Jose Sharks from Minnesota in the Disperal Draft on May 30, 1991. He was a well-thought of prospect by the expansion team, despite his relatively small size (5'11" 190lbs) for a NHL rearguard.
Pat split his first season in the San Jose organization between the Sharks and their farm team, the Kansas City Blades. He appeared in 37 games for San Jose scoring five goals and adding 11 assists for 16 points. Pat had a strong training camp with the Sharks that year and continued his early success in his first game with the Sharks, scoring a pair of goals in the first game in San Jose Sharks team history on October 4, 1991 at Vancouver. The Sharks lost the game to the Canucks, 4-3 in overtime. MacLeod split an injury riddled 1992-93 season between San Jose and Kansas City, appearing in 18 games for the Blades and 13 games for the Sharks.
Despite playing impressively at the minor league level and at times at the NHL level, Pat signed with the Milwaukee Admirals of the IHL in 1993. He responded with his best pro year scoring 21 goals and 52 assists in his 73 games, good enough to be named to the IHL First All-Star team following the season...Returned to Milwaukee for the 1994-95 season and scored 47 points on 11 goals and 36 helpers.
Pat signed with the Dallas Stars as a free agent on July 31, 1995 but spent the 1995-96 season with the farm team. MacLeod did appear in a pair of games for the Stars against San Jose and Vancouver in December 1995.
Without an NHL contract for 1996, Pat began the 1996-97 season playing in Sweden before deciding to move his family back to the States in December. He appeared in 12 games for Farjestad, registering three points on one goal and two assists. He ended up signing an IHL contract to help extend his professional hockey career.
Pat MacLeod was a good defenseman, but not quite good enough to stick in the NHL.