In June 1987 Williams was 19 years old and in his first year of studies at the University of Oxford when he started work as an in-betweener on "Who Framed Roger Rabbit", working under animator Simon Wells and later as an assistant animator to Marc Gordon-Bates. Williams initially worked unpaid as an intern, and was later invited by producer Patsy de Lord to work on the film full-time. The university agreed to his taking a suspension of studies for a year. The following year, in 1988, he joined the Disney-MGM Studio in Orlando, Florida, working on the short film RollerCoaster Rabbit.