Tori Spelling spotted him on a forgettable NBC sitcom called Sister Kate and told her father Aaron Spelling to give him an audition. That call got him the role of Brandon Walsh on Beverly Hills, 90210 in 1990. The show ran for 10 years. He appeared in 245 episodes, earned two Golden Globe nominations, directed 15 episodes, and worked his way up to executive producer by 1995. He left the acting side in 1998 when his character was written off to Washington D.C., but stayed on as EP until the show ended in 2000. He'd already figured out which side of the camera interested him.
The BH90210 revival in 2019 lasted one season, which tells you most of what you need to know about nostalgia as a business model. His actual second act landed in Canada, where he ran the procedural Private Eyes for five seasons from 2016 to 2021. His 2013 feature directorial debut Cas & Dylan, starring Richard Dreyfuss and Tatiana Maslany, won the Whistler Film Festival audience award and almost nobody saw it. He's been a working director and actor for decades. The teen idol thing is a costume he took off a long time ago.
During a practice session for an Indy Pro Series race at Kentucky Speedway in August 2002, his car hit a patch of absorbent material spread to soak up spilled oil, and he went into both walls at nearly 180 mph. He broke his back, both feet, and his nose, and was reportedly clinically dead for 45 seconds. He'd been a competitive driver since 1991, which made the accident less surprising to anyone who knew him. Years earlier, he'd punched Harvey Weinstein at a Miramax Golden Globes party. That story didn't surface publicly until 2017.