His christened name is Mark Linn Baker (without the hyphen). Linn is actually his middle name, not part of his last name. When he joined the actors union, there already was a Mark Baker, so he combined his middle name with his last name. His father made up his middle name "Linn" in honor of Leonid Tolstoy.

He appeared in the role of Hysterium in the 1995 Broadway stage production of `A Funny Thing Happened on the Way to the Forum`.

Played "Marvelous" Mark Slackmeyer in the Broadway production of "Doonesbury - The Musical".

Mark is a partner in Manhattan`s West Bank Cafe.

Appeared in My Favorite Year and Laughter on the 23rd Floor, both based on the real-life writing teams for Sid Caesar`s Your Show of Shows.