<P> The film was directed by Robert Mulligan , and starred Gary Grimes as Hermie , Jerry Houser as his best friend Oscy , Oliver Conant as their nerdy young friend Benjie , Jennifer O'Neill as Hermie 's mysterious love interest , and Katherine Allentuck and Christopher Norris as a pair of girls whom Hermie and Oscy attempt to seduce . Mulligan also has an uncredited role as the voice of the adult Hermie . Maureen Stapleton ( Allentuck 's real - life mother ) also appears in a small , uncredited voice role ( calling after Hermie as he leaves the house in an early scene , and after he enters his room in a later scene ) . </P>
who starred in the movie summer of 42
Gary Grimes Jerry Houser Oliver Conant Jennifer O'Neill Katherine Allentuck Christopher Norris Maureen Stapleton