Stearns was also a stage actor, his first stage appearance was in New Faces and he was in several musical shows, including Show Boat. During World War II he performed for the U.S. military in The Barretts of Wimpole Street. They gave 140 performances for American soldiers in Italy and France, and then, in 1945, they moved to Boston and other New England theaters and then the Barrymore Theater in New York City. Other than playing a role in the show, Stearns visited hospitals during the day to entertain the men who could not go to the show. The American Theatre Wing War Players was the first all-star war theatre to take repertory overseas. Under the orders from Army Special Services, they played as close to battlefronts as possible. Other than Stearns, actor and musician, the play starred Katherine Cornell and Brian Aherne as main leads, and featured McKay Morris, Margalo Gillmore, Brenda Forbes, Betty Brewer, Elaine Perry, William Noon, Emily Lawrence, Gertrude Macy, Chester Stratton, Eric Martin, Keinert Wolf. They were directed by Guthrie McClintic, who doubled as actor, and Robert Ross, who was both director and musician. Nancy Hamilton and Morgan Lewis were the writers of book, lyrics and music.
