Michaels was an original trainer on the reality series "The Biggest Loser" when the show debuted in October 2004. On the show, she assumed the role of Red Team trainer and remained in that capacity for the first two seasons. After her departure in 2006, she was replaced by Kim Lyons. She returned to the show in 2007 as the Black Team trainer competing against Lyons' Red Team and Bob Harper's Blue Team. Along with Harper, Michaels was also a trainer in the Australian version of the show from 2006 to 2008.