To make ends meet during the Academy's vacations, he was forced to do a variety of jobs, including working on the Thames River Bus and selling razors.

He also appeared in The World of Suzie Wong, The Big Killing, A Murder is Announced, The Mousetrap and had three years from 1968-70 playing both Andrew Hunter and Robert Danvers in the London West End stage version of There's a Girl in My Soup.

Later in his career Coleman became a theatre producer and, among other ventures, toured Canada in 1976 with a well-received production of "Absurd Person Singular", starring John Thaw.

1959 Suzie Wong (Ben Jeffcoat) 1962 The Big Killing 1968-70 There's A Girl in My Soup (Andrew Hunter and Robert Danvers) 1975 How It Can Ruin Your Health 1975 Cheaper by the Dozen 1976 Absurd Person Singular (Tour of Canada) 1976 The Roaring Forties (George) 1977 The Chiltern Hundreds (Beecham) 1977 A Murder is Announced 1978 Suddenly At Home (Glenn Howard) 1979 An Ideal Husband (Sir Robert Chiltern) 1982 Public Relations 1982 In Praise of Love.

[3] Coleman also made guest appearances in television series such as Dixon of Dock Green, No Hiding Place, Emergency Ward 10, Sergeant Cork, Zero One, The Avengers, Z-Cars, Thriller (A Coffin for the Bride), Robin's Nest, Surgical Spirit, Champion House, "Letters From The Dead", Whodunnit?

Coleman appeared in a number films including The Dam Busters (1955), Yangtse Incident (1957), Girls at Sea (1958), The Navy Lark (1959), Ben-Hur (1959), Hell is a City (1960), The Day The Earth Caught Fire (1961), 80,000 Suspects (1963), Rotten to the Core (1965) Naked Evil (1966) and Who Dares Wins (1982).