Fisher grew up playing hockey in the Peterborough Minor Hockey Association (OMHA) with the rep Minor Petes program. He was drafted from the Peterborough Roadrunners of the Jr. OHL by the Sudbury Wolves in the second round, 22nd overall, in the 1997 OHL Priority Draft. After putting up 49 points in 66 games in his first year with the Wolves, Fisher was drafted in the second round, 44th overall, by the Ottawa Senators in the 1998 NHL Entry Draft. Returning to the OHL for one more season, Fisher recorded 106 points, fifth overall in league scoring.
He is known for his grittiness and two-way play, being named a finalist for the Selke Trophy in 2006 with the Ottawa Senators. At the beginning of the 2009–10 NHL season, he was named an alternate captain for the Senators. On February 10, 2011, Fisher was traded to the Nashville Predators.