This intense player became interested in acting while attending college on a football scholarship. Petersen initially worked on the Chicago theater scene and even started his own avant-garde company, the Remains Theater Ensemble in 1979. In the '80s, this athletic performer segued to film and TV roles, often playing obsessive law enforcement officials. Although born and bred in Illinois, Petersen had the charisma (if not the accent) to play two members of the Kennedy clan, Joseph in the 1990 miniseries The Kennedys of Massachusetts and John F. in the 1998 TV-movie The Rat Pack. Yet Petersen didn't become a full-fledged star until 2000 when he signed on to produce and star in the original CSI franchise as a sexy Las Vegas criminologist.