After doing his schooling in Dungannon he attended Trinity College, Dublin but left after a short time.

Having a boyish passion for the sea, he found work as a Mercantile Marine with the East India Company, which disappointed his father, who had wanted him to become a solicitor.

Back in Australia, Thornton resumed work as a public servant and was transferred to Moreton Bay as a Collector of Customs for the New South Wales Government.

He served for thirteen years before being forced to resign on the 8 September 1879 due to still being a public servant.

Thornton died at Kangaroo Point in 1884[1] and was buried in South Brisbane Cemetery.