During World War I, she lent her image and name to an American Red Cross campaign for the employment of disabled veterans.

[3] On Broadway,[4] she was in a revival of The Squaw Man (1921) by Edwin Milton Royle,[5] Rose Briar (1922) by Booth Tarkington,[6] The Virgin of Bethulia (1925) by Gladys Buchanan Unger, The School for Scandal (1925), The Pearl of Great Price (1926), The Dark (1927), Mrs. Dane's Defense (1928), Within the Law (1928) by Bayard Veiller, Sherlock Holmes (1928), Serena Blandish (1929), The Rhapsody (1930) by Louis K. Anspacher, The Wiser they Are (1931), and Hay Fever (1931–32) by Noël Coward, with Constance Collier.

Her fashion business, named Julia Hoyt Modes, designed dresses and coats sold in department stores across the United States.

[9] Julia Hoyt was considered a great beauty,[10] and sat for portraits by Paul Helleu, Neysa McMein (for the cover of Woman's Home Companion in 1921 and McCall's in May 1923), John Singer Sargent and Carl Van Vechten.

[15] Hoyt had several health problems in the late 1930s, including pneumonia while at sea in 1935,[17] and a lasting chest infection that necessitated the removal of ribs.