Guardino was born on December 23, 1925[1] on the Lower East Side of Manhattan and raised in Brooklyn, New York.

[2] He joined a Police Athletic League dramatic group while attending high school.

His Broadway theatre credits included A Hatful of Rain, One More River (earning a Tony Award nomination for Best Featured Actor in a Play for his performance), Anyone Can Whistle, The Rose Tattoo, The Seven Descents of Myrtle, and Woman of the Year.

He made guest appearances in dozens of television series, including Studio One, Target: The Corruptors!, The Eleventh Hour, Untouchables, Alfred Hitchcock Presents, Kraft Television Theatre, Playhouse 90, Dr. Kildare, The Lloyd Bridges Show, Route 66, Ben Casey, Hawaii Five-O, Night Gallery, Twelve O'Clock High, Love, American Style, The Greatest Show on Earth, Kojak, Wonder Woman 1978 TV series episode 'The Girl from Ilandia', Hunter, The F.B.I., The Streets of San Francisco, Jake and the Fatman, and Cheers.

[5] Guardino died of lung cancer in Desert Hospital in Palm Springs, California on July 17, 1995.