[3] Smith was inclined towards the stage: upon arrival in London, he applied to John Rich at the original Covent Garden Theatre, where he first appeared in January 1753 in the role of Theodosius (in Nathaniel Lee's tragedy of The Force of Love[4]), a performance attended by many of his college friends in a spirit of solidarity.

At the end of season in 1774 he and the actress Elizabeth Hartley, who played his on-stage lover in Henry II or The Fall of Rosamond, caused a scandal when they absconded to France.

Though for a long time he played lead roles in tragedy, for which he had a suitably tall and well-proportioned figure, his facial features lacked the flexibility and expressiveness, and his vocal delivery was somewhat too harsh and monotonous, to be considered ideal.

[9] However, he won popularity as Richard III, Hotspur, and Hastings, and was also admired in the roles of Kitely (Every Man in his Humour, in which he was preferred to Garrick[10]), Archer, and Oakly.

Smith's masterpiece was his impersonation of Charles Surface in Richard Brinsley Sheridan's The School for Scandal,[12] which won the highest praise for originality, boldness of conception, truth, freedom, ease, and gracefulness of action and manner.

[13] He is mentioned favourably in Charles Lamb's Essays of Elia:"...it was then the fashion to cry down John Kemble, who took the part after Smith; but, I thought, very unjustly.

"[14]On 9 March 1788, after a performance of Hamlet, Smith announced his intention to retire and "resign the sprightly Charles to abler hands and younger heads".