His best known act was as a stuntman character called "Sylveste McCoy" in a play entitled An Evening with Sylveste McCoy (the name was coined by actor Brian Murphy, who worked beside Kent-Smith at the Roundhouse Theatre and originated in the Wolfe Tones version of "Big Strong Man"[8]), where his stunts included putting a fork and nails up his nose and stuffing ferrets down his trousers, and setting his head on fire.

Canadian critic Milton Shulman believed McCoy's name and fictionalised biography were genuine in his review of the Roadshow.

Every episode of the innovative ATV schools maths programme Leapfrog featured McCoy as "Bert" in wordless sequences filmed out of doors, as he attempted to form regular geometric patterns from different numbers of logs or carpet squares.

He also appeared in Eureka, often suffering from the effects of inventions of Wilf Lunn, and as Wart, assistant to StarStrider in the Children's ITV series of the same name.

McCoy also had a small role in the 1979 film Dracula opposite Laurence Olivier and Donald Pleasence, and has sung with the Welsh National Opera.

The Seventh Doctor developed into a much darker figure than any of his earlier incarnations, manipulating people like chess pieces and always seeming to be playing a deeper game.

[12] McCoy's television roles since Doctor Who have included Michael Sams in the 1997 drama Beyond Fear, shown on the first night of broadcast of Channel 5.

In 1988, while still appearing in Doctor Who, McCoy presented a BBC children's programme called What's Your Story?, in which viewers were invited to phone in suggestions for the continuation of an ongoing drama.

In 2001 he appeared in Paul Sellar's asylum comedy "The Dead Move Fast" at the Gilded Balloon as part of the Edinburgh Festival Fringe, playing the role of Doctor Mallinson.

[16] In May 2008 he performed with the Carl Rosa Opera Company in a production of Gilbert and Sullivan's The Mikado, playing the title role.

[19][20] In January and February 2016, McCoy appeared in the three-part BBC series The Real Marigold Hotel, which followed a group of celebrity senior citizens including Miriam Margolyes and Wayne Sleep on a journey to India.

[21] In 2017 he returned to the stage at the Edinburgh Fringe, in the production A Joke alongside Star Trek: Voyager actor Robert Picardo.

He portrays the wizard Radagast,[23] alongside fellow King Lear actor Ian McKellen who reprises his role as Gandalf.