The engaging, attractive Kathleen Quinlan made her first (uncredited) screen appearance as Trish Van Devere's double in a diving scene in 1972's "One Is a Lonely Number". The following year, George Lucas visited her high school and cast her in a small role in "American Graffiti" (1973). She subsequently played a teenager with a crush on Sam Elliott's "Lifeguard" (1976) before landing her first leading role as a schizophrenic teenager in the absorbing, often disturbing drama "I Never Promised You A Rose Garden" (1977). Her restraint in a role that could have easily lapsed into histrionics drew