Psych's protagonist is played by an English actor.
Sir Michael John Gambon ( born 19 October 1940 ) is an Irish-born English actor who has worked in theatre , television and film . Psych . The program also stars Dulé Hill as Shawn 's best friend and reluctant partner Burton `` Gus '' Guster , as well as Corbin Bernsen as Shawn 's father , Henry , a former officer of the Santa Barbara Police Department .