One of several goaltenders who played in the Florida College Hockey Classic, Underhill backstopped the Big Red from 1998 to 2002. He joined the Pee Dee Pride for his first professional season in 2002-2003, posting a 16-13-2 record with a 2.81 GAA and .907 save percentage.

A 6th round draft pick by the Calgary Flames in the 1999 NHL Entry Draft, the Campbell River, British Columbia native has played in the Bruins, Maples Leafs and Chicago organizations, and appeared in 1 NHL game with the Blackhawks. In 2006, Underhill lead the Alaska Aces to their first ECHL Kelly Cup Champinship.