Yass, New South Wales
Cusack was born at Bellevale near Yass, New South Wales and had some schooling in Yass. He was apprenticed at 15 to a blacksmith at Berrima. He learnt about coachbuilding in Sydney and returned to Yass in 1898 to marry Minnie Cassidy and start a coachbuilding business. He was elected to Yass Municipal Council and was mayor in 1904.