A former American football defensive lineman in the American Football League (AFL) and the National Football League (NFL). After playing college football for Northern Arizona, Mirich was drafted by both the AFL and the NFL in 1963. He was selected by the Minnesota Vikings in the 16th round (212th overall) of the 1963 NFL draught and by the Oakland Raiders in the 20th round (153rd overall) of the 1963 AFL Draft. He played seven seasons for the AFL's Oakland Raiders (1964–1966) and Denver Broncos (1967–1969), and the NFL's Boston Patriots (1970).