The son of a rabbi, Segal attended Midwood High School in Brooklyn and traveled to Switzerland to take summer courses. A brilliant student, he attended Harvard University, graduating as both the class poet and Latin salutatorian in 1958 after which he obtained his Master's degree and a Doctorate. He was a professor of comparative literature at Yale University and in 1967, from the story by Lee Minoff, he wrote the screenplay for The Beatles 1968 motion picture, Yellow Submarine.

In the late 1960s, Erich Segal collaborated on other screenplays and also had written a romantic story by himself about a Harvard and a Radcliffe student, but failed to sell it. However, literary agent Lois Wallace at the William Morris Agency, suggested he turn the script into a novel and the result was a literary and motion picture phenomenon called Love Story. A New York Times No. 1 bestseller, the book became the top selling work of fiction for all of 1970 in the United States and was translated into more than twenty languages worldwide. The motion picture of the same name was the number one box office attraction of 1971.

Erich Segal went on to write more novels and screenplays including the 1977 sequel to Love Story, called Oliver's Story. He has published a number of scholarly works as well as teaching at the university level. He has acted as a visiting professor for the University of Munich, Princeton University, and Dartmouth College.

Segal has been married to Karen Marianne James since 1975; they have two daughters.