[2] Before going off to Vassar for college, Phelps attended Bryn Mawr School in Baltimore along with future actresses Margaret Barker and Mildred Natwick.
Her father opposed her desire to appear on stage but her mom assisted her by introducing her to actor George Arliss.
She joined the University Players Guild for its first season of summer stock in West Falmouth on Cape Cod in 1928 along with Henry Fonda, Joshua Logan, Bretaigne Windust, Charles Leatherbee, Myron McCormick, Kent Smith, and others.
At the end of the University Players 1928 summer season, Phelps left Cape Cod to join Arliss and company and never returned to Falmouth.
Among these are Cinderella (1957), Hallmark Hall of Fame (1961), The Catholic Hour (1967), The Secret Storm (1954), Somerset (1975), Threesome (1984), and Kate & Allie (1989).