He emigrated to Port Phillip (now Victoria) in 1840, after entering himself for the bar at Lincoln's Inn, and engaged in pastoral pursuits with his brother Edward, afterwards a well-known physician in Melbourne.
Revisiting England, he was called to the bar in 1843; and in 1844 married Susanna, daughter of Richard Hodgkinson, of Morton Grange, Nottingham.
He returned to Port Phillip in November 1844, accompanied by his brother William (who subsequently practised as a surgeon at Emerald Hill, Melbourne).
In the next year he was appointed a magistrate, and in August 1849 was one of the Commissioners under the Disputed Boundaries Act, having the Hamilton district assigned to him.
[citation needed] Barker, who was admitted to the Victorian bar in November 1851, was in October of that year, on the separation of Port Phillip from New South Wales and its formation into the colony of Victoria, appointed Clerk of the Legislative Council then constituted, and successfully performed the difficult task of inaugurating its procedure.