Cornelius Delohery started public service in NSW as a government letter-carrier in 1830 and a short time later was stationed at Liverpool as inspector of slaughterhouses. In 1831 he was clerk to the Bench of Magistrates at Liverpool. In 1840 he was appointed chief of police but was dismissed for insubordination after making an official complaint against his superior. His grievances with the NSW Police Department continued long after he left the force.

Delohery first exhibited his artworks in 1847 with the Society for the Promotion of the Fine Arts in Sydney. He occupied an office in Surry Hills, advertising himself as a portrait artist. This self-portrait was exhibited in 1857 at the Sydney Mechanics School of Arts. Delohery’s grandson donated it to the Mitchell Library in 1953.