 After leaving the Army, Shimomura began working as a commercial artist and designer – including work on the Polynesian Pavilion at the New York World's Fair in 1964 – but was soon feeling unhappy with the limitations of the field.He began taking painting classes at the University of Washington, where, under the influence of the emerging Pop Art movement, he discovered the possibilities in combining fine art with his lifelong interest in pop culture.Transferring to Syracuse University in New York, where he experimented with filmmaking and performance art, he received his MFA in 1969.