McDermott made his screen debut in "Hamburger Hill" in 1987 before starring in the 1989 film "Steel Magnolias" opposite Julia Roberts as her husband Jackson Latcherie. He also starred in "Twister", a film about a man trying to rescue his girlfriend and daughter from a tornado storm. The same year brought "Neon Empire", a film about the rise and fall of one man in Las Vegas. However, his first big break as an actor was in the film "In the Line of Fire". Through his connection with Clint Eastwood, McDermott was able to land his first major gig in "The Practice". The show expanded McDermott's stardom, and he made "People" list of the "50 Most Beautiful People in the World 1998" with the magazine calling him "a prime-time heartthrob". He got this distinction again in 2000. Despite his success on "The Practice", McDermott was cut from the show. Executive producer David E. Kelley cited "economic and creative realities" as a result of pressure from ABC to reduce costs. McDermott did appear in the final two episodes of the final season.