[1] George Clarke began a career as an actor in the theatre and "quickly attained a position of prominence on the English stage".

[1] In September 1899 Clarke was a cast member in Zaza, an English-language adaptation of a French play, produced by Charles Frohman at New York's Garrick Theatre.

[6] Clarke was a cast member of Shakespeare's Romeo and Juliet, a production by Liebler & Co. at the Knickerbocker Theatre on Broadway.

[9] He played the role of "the seigneur" in the romantic drama The Harvester (an English adaptation of Le Chemineau) which opened at New York's Lyric Theatre on 10 October 1904.

[1] In 1910 Clarke was recorded as working as a theatre manager and living with his brother Franklin in Ward 12 of Manhattan, New York.

[4][13] In August 1912 Clarke travelled to Los Angeles to supervise "the business interests" of The Drums of Oude vaudeville production at the Orpheum Theatre.

Throughout his decade-long career as an actor in silent films he mainly played secondary or utility acting roles, often depicting an elderly character.

[17] In early 1915 Clark was one of the cast members of Road O' Strife, a fifteen-part serial directed by John Ince and produced by the Lubin Manufacturing Company.

[19] He appeared in about twenty Lubin productions, both multi-reel features and ten short films, released in the period from April 1915 to July 1916.

[20] In early 1916 Clarke was in the supporting cast of The Flames of Johannis, a five-reel Lubin production with Nance O'Neil in the dual lead roles.

[22] In 1924 Clarke was cast as Lord Chamberlain in D. W. Griffith's historical romantic film America, set during the events of the American Revolutionary War.

[23] Later in 1924 he was cast as Lord Chesterfield in the historical romantic drama Monsieur Beaucaire, a major production by Paramount Pictures with Rudolph Valentino in the lead role.