Leitch was born in Leeton; his maternal grandfather was William Killen, a member of the Australian House of Representatives from 1922 to 1931.
He studied medicine at the University of Sydney and was subsequently appointed an honorary surgeon to the Armidale and New England Hospital.
In 1942, he enlisted in the AIF and was posted to New Guinea, where he fought the Japanese at Shaggy Ridge.
[1] In 1973, the Country Party member for Armidale, Davis Hughes, resigned to accept the post of Agent-General in London.
He held the seat at the 1973 and 1976 elections, but he was defeated in 1978 by Labor candidate Bill McCarthy.