Theresa Helburn was born on January 12, 1887, in New York City, the younger of two children of Hannah (Peyser) and Julius Helburn. Her father was a leather merchant; her mother, who became Helburn’s role model, established her own experimental elementary school. An assimilated Jew, Helburn attended Horace Mann, the fashionable Windsor School in Boston, and Bryn Mawr College. She graduated in 1908 with many senior prizes, having organized, directed, and acted in all the school plays. She continued her education at Radcliffe College, in George Pierce Baker’s celebrated playwriting workshop, English 47, and at the Sorbonne. She joined the Poetry Society of America, created a course in Shakespearean acting at Miss Merrill’s Finishing School, Mamaroneck, New York, and wrote drama criticism for The Nation.