Glenn Martin Christopher Francis Quinn (May 28, 1970 -- December 3, 2002) was an Irish actor. While he was best known for his portrayal of Mark Healy on the popular ' 90s family sitcom Roseanne, Quinn also amassed a large fan base for his portrayal of Doyle, a half - demon, on Angel, a spin - off series of Buffy the Vampire Slayer.
who played mark on the tv show roseanne
Glenn Martin Christopher Francis Quinn