Doyle is the younger brother of Jerry Only, and the two are famed for playing together in the horror punk band Misfits.
He married Stephanie Bellars ((#invalid artist link ID#)) on September 1, 2001. They have a daughter, Boriss. They later divorced and as of early 2014 he was dating Alissa White-Gluz.
In recent years Doyle has patched up his differences with former Misfits bandmate Glenn Danzig - Danzig produced Gorgeous Frankenstein's debut album and Doyle has appeared onstage to play Misfits songs at Danzig gigs.