Shortly after the latter promotion he was placed on half pay, but exchanged into the 10th Foot in 1829, serving with that regiment for the remainder of his active career.

[5][6] For much of that time the 10th was stationed in the Ionian Islands,[7] and Dunne was awarded the Order of St Saviour of Greece.

[9][10] Dunne sat as Member of Parliament for the Irish constituency of Portarlington from 1847 to 1857, and held the office of Clerk of the Ordnance 1852–53.

[11] As a backbencher he frequently took a leading role in debates on military issues, and was sometimes jokingly referred to as 'the Honourable Member for the Army'.

[12] He was private secretary to the Lord Lieutenant of Ireland, the Earl of Eglinton, in 1858–59, and afterwards returned to the Westminster Parliament as MP for Queen's County 1859–68.