He was born Edward Byrne Breitenberger. He had two siblings, Vincent and Jo-Ann. When he was 13, his father died. He then dropped his last name in favor of "Byrnes" based on the name of his maternal grandfather , Edward Byrne, a fireman. Byrnes developed the urge to act at high school but did not seriously consider it until after he had tried a number of different jobs, such as driving an ambulance, roofing and selling flowers.