Segal is best known for writing Love Story, a novelized version of a 1970 screenplay about two lovers, well-heeled Oliver Barrett IV and working-class Jennifer Cavilleri, who fall in love and marry despite the disapproval of Oliver's family. The book spent more than a year on the best-seller list. The film version, also released in 1970, starred Ryan O’Neal and Ali MacGraw, is credited with ushering in the era of the modern blockbuster. The film earned seven Academy Award nominations and won for Best Score. Segal, a Yale classics professor from 1960s to the 1980s, also wrote Oliver's Story, a sequel to Love Story, Doctors, and The Class.