John Grayson was the father of Dick Grayson.
Together with his wife and son, John formed the Flying Graysons, an acrobatic team performing for Haley's Circus. They performed death-defying stunts without the aid of a net. One night, John and his family performed their usual act, unaware that Tony Zucco had sabotaged the trapeze. During the show, in front of the entire crowd and young Dick, John and Mary fell to their deaths when the line snapped.