[1] He made his professional stage debut at the Kingsway Theatre in 1913 in Arnold Bennett's The Great Adventure, succeeding Clarence Derwent in the role of Ebag.
[1] In 1914 on the outbreak of the First World War Clarke-Smith joined the Royal Artillery, and was mentioned in despatches three times.
[2] In 1919 he joined the Birmingham Repertory Company where his roles included Young Marlowe in She Stoops to Conquer, John Worthing in The Importance of Being Earnest, Joseph Surface in The School for Scandal and in Shakespeare, Malvolio in Twelfth Night, Benedick in Much Ado About Nothing, Shylock in The Merchant of Venice and Hotspur in Henry IV, Part 1.
[1] In the 1920s and 1930s Clarke-Smith was often seen on the West End stage in new plays including Six Characters in Search of an Author, and also in classics, playing Bonnington in The Doctor's Dilemma, Rank in A Doll's House, Kroll in Rosmersholm, Brack in Hedda Gabler and Solness in The Master Builder, and Shakespearean roles including Peter Quince in A Midsummer Night's Dream, Malvolio and Benedick.
Clarke-Smith's post-war stage career followed the pattern of his earlier years, interspersing new commercial plays with revivals of classics.