Her repertoire included plays by James M. Barrie, William Shakespeare, Noël Coward, Robert Browning, A.A. Milne, and George Bernard Shaw.

[5] Barrett is often mentioned in a troika of Broadway stars of the 1930s alongside Eva Le Gallienne, Katherine Cornell, and sometimes Helen Gahagan.

Former New York Times drama critic Brooks Atkinson said of this role that Barrett gave “one of her best performances, if not the best performance, of her career.”[7] In total, Barrett's Broadway credits include Wuthering Heights (1939), The Shoemakers' Holiday (1938), Wise Tomorrow (1937), Parnell (1936), Symphony (1935), Piper Paid (1934), Allure (1934), Moor Born (1934), Strange Orchestra (1933), The Perfect Marriage (1932), Troilus and Cressida (1932), Mrs. Moonlight (1930), Michael and Mary (1929), Becky Sharp (1929), The Phantom Lover (1928), Caponsacchi (1926), The Immortal Thief (1926), King Henry IV, Part I (1926), The Servant in the House (1926), Cyrano de Bergerac (1926), The Merchant of Venice (1925), Hamlet (1925), and Trelawny of the "Wells" (1925).

[8] After starring on Broadway often as the romantic heroine, her Hollywood career started as a character actress in 1941 in a film noir directed by Charles Vidor, Ladies in Retirement.

[citation needed] In the mid-1950s, Barrett revived her career on television in a series of appearances in character roles in Alfred Hitchcock Presents.

Barrett dedicated much of her later life to supporting fellow New York stage actresses who struggled in the motion picture and television industries.

Reflecting on her own declining success in film and television, Barrett often remarked, “the screen just didn’t like me,” suggesting she felt she wasn’t photogenic.