He had inherited his father's peerage in October 1694 and assumed his seat in the Irish House of Lords on 21 September 1703.
He served on several committees in Parliament, aligning himself with the Whig faction and strongly supporting the Hanoverian succession.
He received a commission in the British Army and by 1710 he was a lieutenant colonel in the Earl of Wharton's Dragoons.
On 30 November 1714, Barry was made a member of the Privy Council of Ireland.
[2] Barry was responsible for rebuilding the family seat at Santry House, Dublin.