Garson Kanin began his show-business career as a jazz musician, burlesque comedian, and actor. He graduated from the American Academy of Dramatic Arts in New York City and made his Broadway debut in Little Ol’ Boy (1933). In 1935, Kanin was cast in a George Abbott play and soon became Abbott’s assistant. Kanin made his Broadway debut as a director in 1936, at the age of 24, with Hitch Your Wagon.

He was a colleague of Thornton Wilder, who mentored him, and an admirer of the work of Frank Capra. Kanin said, “I’d rather be Capra than God, if there is a Capra.” Kanin and Katharine Hepburn were the only witnesses to Laurence Olivier and Vivien Leigh’s wedding in California on August 31, 1940. In 1941, Hepburn and he worked with his brother Michael Kanin and Ring Lardner, Jr., on the early drafts of what became Woman of the Year right before Garson enlisted in the army. He is also quoted as saying, “When your work speaks for itself, don’t interrupt.”

Kanin’s best-remembered screenplays, however, were written in collaboration with his wife, actress Ruth Gordon, whom he married in 1942. Together, they wrote the many screenplays, including six that were directed by George Cukor. These included the Spencer Tracy – Katharine Hepburn film comedies Adam’s Rib (1949) and Pat and Mike (1952), as well as A Double Life (1947), starring Ronald Colman.

In 1945, Kanin directed Spencer Tracy in Tracy’s first play in 15 years. Tracy had been through a dark patch personally, culminating with a stay in hospital, and Katharine Hepburn felt that a play would help restore his focus. Tracy told a journalist in April, “I’m coming back to Broadway to see if I can still act.” The play was The Rugged Path by Robert E. Sherwood, which first previewed in Providence, Rhode Island, on September 28, to a sold-out crowd and tepid response.

The Rugged Path was a difficult production, with Kanin later writing, “In the ten days prior to the New York opening, all the important relationships had deteriorated. Spencer was tense and unbending, could not, or would not, take direction”. Tracy considered leaving the show before it even opened on Broadway, and lasted there just six weeks before announcing his intention to close the show. It closed on January 19, 1946, after 81 performances. Tracy later explained to a friend: “I couldn’t say those goddamn lines over and over and over again every night … At least every day is a new day for me in films … But this thing—every day, every day, over and over again.”

Kanin’s 1946 play Born Yesterday, which he also directed, ran for 1,642 performances. Kanin worked, uncredited, on the screenplay of the 1950 film adaptation. His other stage work includes directing The Diary of Anne Frank (1955), which ran for 717 performances, and the musical Funny Girl (1964), which ran for 1,348 performances. Kanin wrote and directed his last play, Peccadillo, in 1985, the same year he was inducted into the American Theater Hall of Fame.

Kanin was married to his frequent collaborator, Academy Award-winning actress Ruth Gordon, from 1942 to her death in 1985. In 1990, Kanin married celebrated stage actress Marian Seldes (1928–2014). In 1999, Kanin died at age 86 in Manhattan of undisclosed causes. Kanin was Jewish.