Cooper was a former employee (and probably an apprentice) of the Melbourne lithographic printing firm Charles Troedel & Co. In 1891, he went into partnership with Charles Troedel, establishing a Sydney printing firm: Troedel, Cooper & Co. The enterprise was short-lived and Cooper returned to the main business in Melbourne. Following the death of Charles Troedel in 1906, Cooper, in partnership with one of Charles' sons, purchased the company from Troedel's estate, establishing the firm of Troedel & Cooper.
