While attending Queen's University, Kingston, Ontario, he became interested in theatre and music and played ice hockey and varsity basketball.

Other stage credits include productions of A Chorus Line, Cabaret, Brighton Beach Memoirs, Urinetown and Grease.

Cavanagh received a Golden Globe nomination and a TV Guide Award for his work on Ed, which ran for four seasons beginning in October 2000 and concluding in February 2004.

[4] Cavanagh guest starred on the sitcom Scrubs where he played Dan Dorian, the brother of Zach Braff's character.

He starred in the Lifetime Movie Network television miniseries The Capture Of The Green River Killer in which he portrayed King County sheriff David Reichert.

Cavanagh portrayed the lead role Nick Snowden (the heir to the Santa Claus identity) in the made-for-TV movie Snow in 2005, which is shown annually on the Family Channel.

From January to April 2009, Cavanagh starred in the television drama Trust Me, co-starring Eric McCormack, which aired on TNT until cancellation due to low ratings.

He made a guest appearance in the mid-season premiere of the USA Network show Royal Pains as former professional golfer Jack O'Malley.

In 2006, Cavanagh began filming Breakfast with Scot, in which he plays a gay retired hockey player who becomes an adoptive father to a young boy.

Cavanagh married Maureen Grise, an image editor for Sports Illustrated, on July 31, 2004, in a Catholic ceremony on Nantucket, Massachusetts.

[22] In summer 2008, he founded the Cavanagh Classic, an annual celebrity basketball tournament in Rucker Park in Harlem to raise money and awareness for Nothing But Nets.