Martin Serious is the balding and obese host of The Martin Serious Show in Grand Theft Auto IV. His show was originally broadcasted on LCFR sometime before 2002, but he was later fired because his antics were too extreme and offensive. Sometime later, his show moved to WKTT where it remained as of 2008. Over the years he has done all kinds of crazy and/or bizarre things for ratings, such as licking a 70 year old woman's vagina, throwing used urinal cakes dipped in glue at Cindy the Intern, and giving ecstasy to mentally handicapped people, while relegating the dangerous acts to his guests or his sidekick Smithy. He did a live read for the Italian American restaurant Al Dente's where he put on an Italian-American voice which was believed to be a mafia impersonation. Martin's mother was once trapped in a limo being ravaged by a tramp on air on June 12th, 2002. He also did a live remote from an abortion clinic.
He is voiced by Will Forte.
- He is a parody of real-life celebrity radio talk show host Howard Stern, who likewise has been accused of being racist, sexist, and homophobic.
- On Integrity 2.0, Lazlow refers to him as a "hack sellout".
- In Grand Theft Auto V, Martin Serious is one of the honored celebrities on the Vinewood Boulevard sidewalk.