He played most of his first four professional seasons for Hartford's minor league teams in Binghamton and Springfield, with some spot duty for the Whalers in 1989, 1990 and 1991.
In the 1991 American Hockey League season, Whitmore led the Springfield Indians to the franchise's seventh and final Calder Cup, and was named the winner of the Jack A. Butterfield Trophy as playoff MVP.
[citation needed] In the 1992 offseason, he was traded to the Vancouver Canucks for Corrie D'Alessio and cash.
He retired from professional hockey thereafter, save for a three-game playoff stint for the Nuremberg Ice Tigers of the Deutsche Eishockey Liga in 2005.
[citation needed] Following his hockey career, Whitmore was the goaltending coach for the Peterborough Petes from 2002-2004.