On June 21, 1963, at age eighteen, Longfellow gave birth to her first child, daughter Sydney Longfellow (who became a painter and photographer as an adult). In 1964 she acted in her only movie, "Once a Thief" (starring Alain Delon and directed by Ralph Nelson), in a part written for her by her close friend, the film's screenwriter Zekial Marko. In 1967 she moved with her daughter to New York City, where she worked briefly as a fashion model, and then as a writer for CARE. She moved to Montana, where she lived and worked for a year on a ranch on the Blackfeet Indian Reservation as a member of VISTA. She sailed to Europe, living for a time in Nice and Paris.