[3] He created the Phoenix Theater, which began with stage productions and then went on radio for a 68-week series of hour-long plays [5] He worked with a group whose members included John Drainie, Lister Sinclair, and Alan Young on such local stations as CJOR, CKWX and the CBC network.

Markle then moved to New York City, and although not listed in the credits, contributed to the screenplay for Orson Welles's The Lady from Shanghai (1947).

[9] During the 1950s and early 1960s, he was a director, producer and host for a number of television series such as Front Row Center and Boris Karloff's Thriller, Father of the Bride, and Telescope.

[9] In 1956, Markle and his wife, Mercedes McCambridge, launched a company to produce feature films and content for independent television.

The stories, which had been published in The Saturday Evening Post, centered around a young Cuban couple and their Cafe Mosca in Havana.

[11] Markle received an Academy Award nomination for the documentary film The V-1: Story of the Robot Bomb,[1] which he wrote and narrated.