Born in Melrose, Massachusetts, Fitzgerald was a scoring star at Austin Prep high school. The New York Islanders chose him 17th overall in the 1986 NHL Entry Draft, before spending two years at Providence College. Fitzgerald played 23 games as an NHL rookie in 1988-89. Most of his first two years were spent honing his skills in the AHL until he was more or less a regular by 1991-92.
Fitzgerald scored 27 points and was a key defensive player when the Islanders upset the defending Stanley Cup champion Pittsburgh Penguins to reach the semi-finals in 1993. A few weeks later he was claimed by the Florida Panthers in the Expansion Draft and assumed greater responsibility with his new team. The hard working forward scored a career high 18 goals in the club's inaugural season in 1993-94. Two years later he scored eight points in 22 playoff games as the Panthers shocked the hockey world by reaching the Stanley Cup finals.
Late in the 1997-98 season, the Colorado Avalanche picked Fitzgerald up at the trading deadline. He was a solid player for them but was not resigned after Colorado failed to win the Stanley Cup. The expansion Nashville Predators signed him as a free agent and he became a team leader on the club as it held its own in the league.
A solid defensive player and penalty killer with the young Preds', Fitzgerald went on to play four seasons in Nashville before he was dealt to the Chicago Blackhawks in the latter half of the 2001-02 season.
Fitzgerald's stay in Chicago was brief, as he would sign with the Toronto Maple Leafs in the off-season. After only two seasons in Toronto, Fitzgerald signed as an unrestricted free-agent with the Boston Bruins in the summer of 2004. Fitzgerald lived out a childhood dream in Boston, appearing in 71 games with his hometown Bruins.
In July 2006, the Boston Bruins opted not to renew Fitzgerald's contract. As a result, the veteran forward announced his retirement on September 12, 2006.