O'Sullivan was also a soldier, and was stationed in London with his regiment when Queen Victoria succeeded to the throne in 1837.

He arrived at Sydney on 21 July 1838, sailing to Australia on the Bengal Merchant and went to work at Illawarra.

He became a store-keeper in Ipswich and received a conditional pardon on 20 October 1849, eventually becoming a successful merchant.

[1] O'Sullivan died of a stroke at his Woodend home[4] and was buried in the Ipswich General Cemetery.

[6] O'Sullivan was defeated at the 1863 election[7] and four years later won a position on the electoral district of West Moreton, also a three-member seat.