Nemec is known for playing the title character in the sitcom Parker Lewis Can't Lose (1990–1993), Jonas Quinn in the science fiction series Stargate SG-1, and Harold Lauder in the miniseries The Stand.

[4][5][6] Nemec began training with the Centre Stage LA theater company and signed on with an agent after performing in one of its talent showcases.

He was booked for several commercials, such as Suzuki, and eventually landed a guest-spot on the TV show Sidekicks starring Ernie Reyes Jr., with whom Nemec is still friends.

He starred alongside actors Jack Palance, Peter Boyle, and Charlton Heston in the 1990 feature film Solar Crisis.

During the 1990s, Nemec had a brief foray into hip-hop,[8] recording an entire album with the group Starship of Foolz, developed by Matt Robinson and Dedra Tate, and produced by actor Balthazar Getty.

The entire right side of his body was shattered; he required multiple blood transfusions to save his life, and he underwent five surgeries.

Nemec is close friends with actor David Faustino of television sitcom Married... with Children, with whom he has a production company that co-produced the debut album from Austin-based band Hollow featuring Jon Dishongh.