Stephen Dunham was born and raised in the Boston area, the middle of three children whose father is a business consultant and mother a real estate agent. While still in high school, Dunham won the lead in Woody Allen's Don't Drink the Water, and continued performing in plays throughout high school. He then attended New York University's Tisch School of the Arts, where he received a Bachelor of Fine Arts degree in theater. While there he also attended the famed Actors Studio. "Every Tuesday and Friday I got to watch actors like Christopher Walken and Robert De Niro getting chastised by our moderator, Ellen Burstyn, for not bringing enough of themselves to the work. It was surreal." Dunham spent his college summers doing improvisational comedy with Boston's On the Spot Players.

After graduation Dunham came to Los Angeles and soon landed various television commercials and guest spots. Between roles, he supported himself by working as a bartender, truck driver, rental car agent and production assistant for infomercials. "I had to quit making infomercials? it was too exciting for me," he says. "So many miracles!"

Dunham received critical acclaim for his leading role in the 1995 independent film, Nothing Sacred. He then found a wider audience when he appeared as the American gunslinger, Henderson, in Universal's blockbuster, The Mummy. Soon after, he won the starring role in the comedy series Oh Grow Up, created and executive-produced by the Oscar-winning writer Alan Ball (American Beauty, Six Feet Under). He was cast opposite David Alan Grier as bumbling secret service agent Edward Pillows in the NBC series DAG. He also spent a season as Jenny Garth's boss and love interest in the WB's What I like About You.

His film credits include working with director Steven Soderbergh in Traffic, with Steven Spielberg in Catch Me If You Can, and with fellow NYU classmate Adam Sandler in Anger Management. His most recent role was as the infamous "Dr. Chamberlain," a struggling actor/waiter who pretends to be a doctor in the feature film Monster-in-Law, starring Jane Fonda and Jennifer Lopez.