Born Leo Melis in Brooklyn on July 15, 1930, he moved with his family to the Lower East Side. He later attended New York University and studied with Lee Strasberg, and Canada Lee, then joined the US Army.
Upon his discharge, he studied with Michael Howard. He did many years in the regional theatre, moving to Broadway and appearing in Zalman or the Madness of God, Grind, and Some of My Best Friends.
Wallace also appeared in such films as Batman, The Taking of Pelham 1-2-3, and Private Benjamin.
Survivors include actress Marilyn Chris, to whom he was married for 45 years; a son, Paul, and his family in Northern California.
Burial will be at Sharon Gardens Cemetery in Valhalla, New York and is for immediate family only.