Glenn Quinn, Irish-American actor (b. 1970)
Glenn Martin Christopher Francis Quinn (28 May 1970 – 3 December 2002) was an Irish actor, best known for his portrayal of Mark Healy on the popular 1990s family sitcom Roseanne and his role as the half-demon Allen Francis Doyle on Angel, a spin-off series of Buffy the Vampire Slayer.