Mark Linn-Baker (born Mark Linn Baker; June 17, 1954) is an American actor and director who played Benjy Stone in the film My Favorite Year and Larry Appleton in the television sitcom Perfect Strangers.

Mark Linn-Baker was born with the given names Mark Linn and the surname Baker in St. Louis, Missouri. He later changed his surname to a compound surname by hyphenating his middle name Linn with his surname Baker, producing Linn-Baker. His mother, Joan (née Sparks), of Jewish ancestry, was a dancer, and his father, William Nelson Baker, co-founded the Open Stage Theater in Hartford. His parents were both active in theatre and participated in civil rights activism.^[2][3][4] He graduated from Wethersfield High School in Wethersfield, Connecticut, in 1972, and from Yale University in 1976. He then attended the Yale School of Drama, receiving a MFA in Drama in 1979, and following that, found most of his early roles on stage.

He developed and performed in a two-man comedy show, The Laundry Hour, with Lewis Black, in the early 1980s.

He appeared in the 1983 Broadway version of the Doonesbury comic strip. He appeared in Laughter on the 23rd Floor in 1993; the 1996 revival of A Funny Thing Happened on the Way to the Forum; the 1998 Roundabout Theatre Company production of A Flea in Her Ear; the 2003 musical A Year with Frog and Toad; and the 2006 comedy Losing Louie.

His film debut was a small part in Woody Allen's 1979 film Manhattan. The majority of Linn-Baker's scenes were cut from the film. Three years later, he landed a far more memorable film role partly inspired by Allen himself, playing Benjy Stone in the 1982 comedy film My Favorite Year alongside Peter O'Toole. In a manner similar to his future role in Perfect Strangers, Linn-Baker played the straight man to O'Toole's outrageous character, Alan Swann.

Having attained success on stage and the big screen, Linn-Baker began to turn his sights toward television. In 1983, he appeared in an unsold detective show pilot called O'Malley. The following year saw a role on the television movie, The Ghost Writer, and in the summer series, The Comedy Zone. Soon, Linn-Baker was appearing in several high-profile television shows. He guest-starred on a 1984 episode of Miami Vice as Bonzo Barry and portrayed hapless office worker Phil West on a 1985 episode of Moonlighting titled "Atlas Belched". Linn-Baker starred with Charles Kimbrough in the 1985 CBS pilot The Recovery Room, a sitcom about a bar located across from a major city hospital and its inhabitants. Airing as a special that summer, the pilot did not lead to a regular series. Between parts, Linn-Baker also appeared during this time in television commercials pitching products ranging from Kellogg's Nutri-Grain to Kraft's Life Savers.

Linn-Baker starred in the ABC series Perfect Strangers as Larry Appleton, a young man living on his own for the first time in Chicago. Larry's world was disrupted when a distant cousin from the (fictional) Mediterranean island of Mypos, Balki Bartokomous (Bronson Pinchot), showed up on his doorstep. Storylines revolved around Larry's attempts to show Balki the ways of American culture, although the neurotic Larry frequently proved to be just as naive as Balki. The series ran for eight seasons. Later, he appeared in Peter Bogdanovich's 1992 film Noises Off.

In 2005, he was a regular cast member on the WB Network sitcom Twins, which was canceled after a single season. He also appeared in the 2010 film How Do You Know as Ron. In 2011, he starred in his sixth Broadway show Relatively Speaking in a one-act play by Woody Allen. He previously appeared opposite Nathan Lane in A Funny Thing Happened on the Way to the Forum. In 2016 he appeared off-Broadway as Sir Peter Teazle in The School for Scandal at the Lucille Lortel Theatre.^[5] As of 2017 he is playing the role of Carlton Miller, aide to Mayor Margaret Dutton (Lorraine Bracco) on the CBS police procedural drama Blue Bloods.

In 2019, he played Mayor George Shinn in the Kennedy Center's production of The Music Man opposite Norm Lewis as Hill and Jessie Mueller as Marian. He reprised his role when he replaced Jefferson Mays in the 2022 Broadway revival, where he performed opposite Hugh Jackman as Hill and Sutton Foster as Marian.

In 1995, Linn-Baker married Adrianne Lobel, the daughter of children's book author Arnold Lobel, best known for his Frog and Toad series.^{[11][citation needed]} They divorced after having one daughter.^[1] Linn-Baker helped adapt his father-in-law's stories into the Tony-nominated Broadway musical A Year with Frog and Toad, in which Linn-Baker played Toad and Jay Goede played Frog. On December 29, 2012, Linn-Baker married actress Christa Justus.^[1]