Waring began his career in 1931 with Eva Le Gallienne's Civic Repertory Theater in New York City in Romeo and Juliet, Camille, and Cradle Song.

Before that, he was filmed in his best-known screen role in Mr. Skeffington (1944) as Fanny Trellis' brother Trippy.

After his war service he appeared on Broadway as the Duke of Buckingham in Henry VIII, John Shand in J.M.

He acted with Katharine Hepburn in The Merchant of Venice, Much Ado About Nothing, and one performance in A Midsummer Night's Dream as Oberon before she had to leave the production.[when?]

[1][2] Waring died of a heart attack on 18 January 1993 in City Island, Bronx, New York.