Wallau, one of seven children, was born January 11, 1945 in Manhattan. He grew up in Connecticut and graduated from Williams College in Massachusetts, after which he began working as a sports writer and editor, plus a public relations consultant on various political campaigns. Wallau joined ABC in 1976 as a producer and director before taking over the on-air boxing analyst job in a newly constructed, two-man broadcast set-up. Prior to taking over broadcast duties, Wallau had been the executive in charge of selecting, negotiating and purchasing the fights that aired on ABC Sports.