Born in Concord, Massachusetts, Sylvia studied theater at the Smith Collegeand with Hallie Flanagan Davis; After graduation, she completed a two-year training at the Old Vic Theater School in London. Upon her return to the United States, she studied with Uta Hagen, winning the Barter Theater Award, awarded by Fredric March in 1952, after which she traveled the country with Barter's repertoire, the first of her many Shakespearean roles of Portia in The Venice.
While raising her two children in New York, Sylvia earned her Ph.D. in marine biology, eventually teaching her at NYU, ocean life being one of her fascinations. She returned to the theater in the late 70s, taught at Juilliard and played in plays at the Phoenix Theater, American Place and Manhattan Theater Club, among others, as well as in Broadway shows.
