After a brief appearance as an extra in the 1961 film "The Explosive Generation", Geffen began his entertainment career in the mailroom at the William Morris Agency (WMA), where he quickly became a talent agent. In order to obtain the WMA job, he had to prove he was a college graduate. As he later reported in an interview, he claimed in his job application at WMA that he had graduated from the University of California at Los Angeles (UCLA). Because he worked in the mailroom, Geffen was able to intercept a letter from UCLA to WMA which stated that he had not graduated from UCLA. He modified the letter to show that he had attended and graduated, then submitted it to WMA. From 1964 to 1968 he was a mailroom clerk and then agent at WMA.