After starting his career as an actor, he worked regularly as a director throughout the 1960s, 1970s and 1980s, which included directing several early serials of Doctor Who starring William Hartnell, and series such as Compact, Crown Court and All Creatures Great and Small.

[3] In 2013, the BBC praised Martin's direction of The Edge of Destruction for how it "wrings every available ounce of suspense, horror and mystery" from a script that features only the show's four regular characters.

[3][7] Wood and Miles consider Martin to have been "hopelessly out of his depth" in directing The Chase, suggesting that the previous story, The Space Museum, would have played to his strengths as a director instead.

[9][10] Martin worked on a great number of television series and documentaries after Doctor Who, including Crown Court, A Family at War, Six Days of Justice, BBC2 Playhouse, Elizabeth R, The Mallens and many others.

In the 2013 docudrama An Adventure in Space and Time, Martin was portrayed by writer Mark Gatiss's husband, actor Ian Hallard.