Ley served in the lower house of the New South Wales parliament (1917–25) as member for Hurstville from 1917 to 1920, representing the Nationalist Party of Australia. He then was member for St George from 1920 to 1925, representing the Progressive Party from 1920 to 1922. The Progressive Party supported proportional representation, which the state adopted in 1919. Both his electorates were in Sydney's southern suburbs.