Born in Indiana and raised in Minnesota, John McMartin attended college in both Illinois and New York. McMartin initially wanted to be a print or radio journalist, but opted instead for acting. His first big break was as Corporal Billy Jester in the 1959 off-Broadway operetta spoof Little Mary Sunshine, which won him both a Theatre World award and a bride (he married Cynthia Baer, one of the show's producers). After appearing in two Bob Fosse-directed productions, he enjoyed a long run as Gwen Verdon's nervous boyfriend Oscar in Fosse's Sweet Charity (1965). He went westward to repeat the role of Oscar in the 1969 film version of Charity, but preferred New York to Hollywood and returned to the stage. In 1971, he was cast as Benjamin Stone in the Stephen Sondheim hit Follies (nine years earlier, he'd been cut from Sondheim's A Funny Thing Happened on the Way to the Forum). He then spent several years playing classical-and non-musical-stage roles. Throughout his Broadway years, he made infrequent film and TV appearances; he played supporting roles in such movies as All the President's Men (1976) and Pennies from Heaven (1980), was briefly a regular on Falcon Crest, guested as Shelley Fabares' father on the sitcom Coach, and was seen in the made-for-TV features Separate but Equal (1991) and Citizen Cohn (1992). One of his most intriguing TV assignments was the 1965 pilot film for the never-sold lawyer series Higher and Higher, in which his co-stars were a couple of green kids named Sally Kellerman and Dustin Hoffman. In the 1990s, John McMartin scored a huge success as Captain Andy in producer Hal Prince's gargantuan revival of Show Boat.