[2] Harrison made her stage debut as Mrs. Judd in The Constant Flirt at the Pier Theatre, Eastbourne in 1926.

Her subsequent West End plays included A Damsel in Distress, Happy Families, The Merchant and Venus, Lovers' Meeting, Line Engaged, Night Must Fall—also acting in the 1937 film version—Flare Path, Ducks and Drakes, The Winslow Boy and Watch It Sailor!.

Harrison also played Kaney in The Ghoul (1933) and the matriarch in Mrs. Gibbons' Boys (1962), as well as two BBC productions of Charles Dickens's novels, Martin Chuzzlewit (1964) and Our Mutual Friend (1976).

She starred on television as Mrs Thursday (1966–67), a charwoman who inherits £10 million and the controlling interest in a major company.

Harrison turned down the title role in writer Jeremy Sandford's Play for Today Edna, the Inebriate Woman (1971).