A Liberal Party politician from Queensland, Chalk held the seats of East Toowoomba (1947-1950) and Lockyer (1950-1976), and was Minister for Transport (August 1957-December 1965), Treasurer (1965-1976), and, for one week, Premier of Queensland (1-8 August 1968): he was replaced by Sir Joh Bjelke-Petersen, who was elected leader of the Country Party, succeeding Jack Pizzey, who had died suddenly on 31 July.