He was a member of the Country Party and served terms in the Western Australian Legislative Assembly (1943–1949) and House of Representatives (1949–1958, 1961–1963).

On 26 December 1931 Leslie married Isabel Margaret Dawson (aged 21), eventually bearing seven children.

[1] Leslie exited the print media in 1939 and became chairman of the Wyalkatchem District Patriotic Committee and the president of the local Returned Sailors' and Soldiers' Imperial League of Australia.

He was elected to the Western Australian Legislative Assembly on 20 November of that year in the seat of Mount Marshall.

[1] Leslie won the Division of Moore on 10 December 1949 and continued a successful political career, including a six-year stint with the Public Accounts Committee from 1952 to 1958.