Singleton was the third son of Francis Corbet, of Aclare, County Meath, Ireland, who assumed the additional name of Singleton in compliance with the will of his great grand-uncle, the Right Hon. Henry Singleton, sometime Master of the Rolls and Chief Justice of the Common Pleas in Ireland.^[1] Singleton entered the Royal Navy in 1825, was present at the capture of the Morea Castle in Greece and left the navy in 1836.^[2] He married Louisa, daughter of Rev. Thomas Gore, of Mulranken, County Wexford.^[1]

Singleton was clerk of the Legislative Council and Government Resident of the Murray district, Western Australia, from 1840 to 1847; a member of the Legislative Council of that colony nominated by the Crown, from 1844 to 1847; Auditor-General of South Australia from 8 May 1847, to January 1851; clerk of the Executive Council of South Australia from December 1850 to December 1851; clerk of the wholly nominated South Australian Legislative Council from December 1850 to August 1851; clerk of the partly elected Council from August 1851 to February 1857; and clerk of the wholly elected Legislative Council, under the Constitution Act, from February 1857 till his death on 10 May 1887.^[1]

The City of Rockingham suburb of Singleton was named after him.^[3]

• Photograph of Singleton at State Library of South Australia
• Obituary at Obituaries Australia