Peck had many television appearances as a young actor, including a younger Michael Kelso (played by Ashton Kutcher) in That '70s Show. In his first film role at age 9, he co-starred in the made-for-TV film Marshal Law as the son of Jimmy Smits' character. He later appeared in the 1999 movie Passport to Paris starring Mary-Kate Olsen and Ashley Olsen, and was Mary-Kate's first on-screen kiss.
Peck co-starred with Adam Rothenberg and Mariah Carey in the 2008 film Tennessee, followed by a co-starring role opposite Peter Coyote and Bebe Neuwirth in the film Adopt a Sailor. He won the award for "Best Actor" at the 2009 Sonoma International Film Festival for his portrayal of "Sailor".
From 2009 to 2010, he starred on the television series 10 Things I Hate About You on ABC Family.
In 2012, Peck played Prince Maxon for the pilot adaptation of the popular book The Selection, but was later replaced by newcomer Michael Malarkey. Neither the first nor second pilot was picked up to go to series.
In 2015, Peck became a spokesperson for fashion brand Salvatore Ferragamo and appeared in a number of print editorials representing the Italian brand. He was also featured in Coming Home to Hollywood, a short film about the brand's 100th anniversary.
In 2016, Peck starred in The Curse of Sleeping Beauty and Tell Me How I Die.
In 2017, Peck was cast in the comedy film The Honor List, alongside Meghan Rienks, Sasha Pieterse, Arden Cho and Karrueche Tran. It was released in 2018.
Peck portrayed Spock in the second season of Star Trek: Discovery. In May 2020 it was announced that he would reprise the role in a spin-off, Star Trek: Strange New Worlds.
