Ernest Alfred Roberts was born in London on 21 February 1868, the son of John Henry Roberts and his wife Sarah Ann Woodford. His father was an officer in the merchant marine. Ernest attended school on the island of Guernsey in the English Channel off the coast of Normandy. He followed in his father's footsteps and became a sailor before settling in Queensland in 1886. Two years later he moved to Port Pirie, South Australia, where he obtained work as a wharf labourer. Described in his entry in the Australian Dictionary of Biography as "[a] radical with exceptional abilities as an orator and organi[s]er", Roberts was closely involved in the formation of a local workingmen's association, becoming its inaugural secretary. He also assisted in the establishment and management of a local cooperative bakery in Port Pirie, and was a member of the town council in the early 1890s. On 27 August 1892, Roberts married Bridget Marie Collins, with whom he had a son and three daughters.
