Born and brought up in St. Louis, Missouri, Passanante began college at Cornell University (as a classmate of Christopher Reeve), but transferred as a sophomore to Dartmouth College, when Dartmouth went co-ed. At Dartmouth, she was a classmate of playwright Peter Parnell and Broadway music arranger Bruce Coughlin. She acted and directed at Dartmouth and after graduation, worked in summer stock in North Conway, New Hampshire, with a group of Williams College grads, including John Sayles, David Strathairn and Adam LeFevre. After moving to New York in 1976, she worked as a theater and literary agent before becoming a theatre producer/administrator. She held management positions for the Eugene O'Neill Theatre Center, New York Theatre Workshop, and New Dramatists before writing for soap operas. She has won three Writers Guild Awards and four Emmy Awards for her work as a writer on various daytime serials. She has been married since 1984 and has one child. She lives in New York City.