McCullough was born at Elmwood Plantation near Little Rock, Arkansas. After moving to Texas, she lived in Eastland (1922-35) and Dallas (1936-41), then became a resident of Laguna Beach, California. She was director of a children's art school in Dallas. McCullough studied at the Academie Julian, Paris, and at the Art Academy of Cincinnati. In Paris she was a student of John LaFarge, Emile Renard, and Gabrielle Debillemont-Chardon. In Cincinnati she was a student of Lewis Henry Meakin, Frank K. Duveneck, and Vincent Nowottny. McCullough coauthored a book on porcelain painting.