After Fahs left Union in 1944, she became editor of "Parents Magazine". In 1945 she joined a Unitarian congregation, and in 1959 she became the first female professor to be ordained as a Unitarian minister. She was ordained by the Cedar Lane Unitarian Church of Bethesda, Maryland (Unitarians and Universalists consolidated in 1961 to form the Unitarian Universalist Association). Beginning in 1937 and continuing until her retirement in 1964, Fahs worked for the American Unitarian Association as an editor of children's materials for a new religious curriculum called "The New Beacon Series." One of her best-known quotes is "Each night a child is born is a holy night."