Mr. Segal was unusual among American popular novelists and American scholars: he was both. In addition to Love Story, the heart-tugging tale of a Harvard scion and his love affair with a Radcliffe scholarship student who dies shortly after their marriage, Mr. Segal wrote several other novels, including Oliver's Story, a sequel to Love Story; The Class, which traces the fates of five members of the Harvard class of 1958; and Doctors, a melodrama about childhood friends who go through medical school together.

After Yellow Submarine, he wrote screenplays for, among other films, Love Story, the 1970 version of the novel that starred Ryan O’Neal and Ali MacGraw, and A Change of Seasons (1980), about a marriage gone awry, with Anthony Hopkins, Shirley MacLaine and Bo Derek.