Career
Born in Cerres, Fifeshire to ploughman Richard Sleath and Mary Fernie, he migrated to Queensland in 1877, becoming a shearer and prospector. In 1882 he moved to Sydney, working as a contractor before mining at Broken Hill from 1887. In 1894 he was elected to the New South Wales Legislative Assembly as the Labour member for Wilcannia.
He lost his Labour endorsement in 1901 but was re-elected as an Independent Labor candidate, losing his seat in 1904.
In 1917 Sleath, a supporter of conscription, joined the Nationalist Party. He died in Sydney in 1922.