He reprised the role of Zack Morris in a recurring capacity for the Peacock sequel series Saved by the Bell (2020) and stars in the NBC procedural drama Found (2023).

[7][8] His Dutch-Indonesian mother, who was born in Bali, Indonesia, was a flight attendant for KLM Royal Dutch Airlines.

[12] He began modeling at the age of five,[3] and as a child, he also appeared in commercials for Cookie Crisp cereal and Smurf merchandise, later winning guest spots on television series.

[15] He spent his teenage years in the Santa Clarita Valley in Southern California, where he attended Hart High School.

[18] Gosselaar first came to public notice as the star of the hit television comedy series Saved by the Bell, which aired on NBC from 1989 to 1993.

In 1994, he appeared as Zack Morris in a second spin-off series Saved by the Bell: The New Class in the episode "Goodbye, Bayside – Part 2", along with Mario López as A.C. Slater and Lark Voorhies as Lisa Turtle.

Later that same year, Gosselaar played the central character in the TV drama Hyperion Bay, which lasted 17 episodes.

During his time on the show, he appeared in Atomic Twister in which he played Jake Hannah, a deputy who is traumatized over his mother's death and must help after a series of tornadoes hits a nuclear power plant in a small Tennessee town; the movie also stars fellow NYPD Blue alum Sharon Lawrence, who plays Corrine Maguire.

He then gained the starring role of defense attorney Jerry Kellerman in the Steven Bochco-produced Raising the Bar, which debuted on September 1, 2008, on TNT, then it was canceled in November 2009 after two seasons.

[19] On June 8, 2009, Gosselaar appeared on Late Night with Jimmy Fallon in character as Zack Morris to promote his show Raising the Bar, indicating that the name Mark-Paul Gosselaar is his stage name and declaring, as Zack, that he would participate in a Saved by the Bell "Class" reunion that is being spearheaded by Fallon.

[21][22][23] In October 2009, he made his off-Broadway stage debut in Theresa Rebeck's play The Understudy with The Roundabout Theatre Company.

[25] The FOX series Pitch cast Gosselaar in the main role of Mike Lawson, star catcher and team captain, in February 2016, and premiered on September 22, 2016.

[28] In a July 2009 interview with People, Gosselaar revealed that while Saved by the Bell was in production, he dated, at different times, his three female co-stars: Lark Voorhies, Tiffani Thiessen,[29] and Elizabeth Berkley.