He was the son of Sir Robert Deane, 5th Baronet of Dromore and succeeded his father in the baronetcy in 1770.
He was also appointed High Sheriff of County Cork for 1773[1] and admitted to the Irish Privy Council in 1777.
[2] In 1783, he was chosen Grandmaster of the Grand Lodge of Ireland, a post he held for the next both years.
[3] Lord Muskerry married Anne, daughter of John FitzMaurice, in 1775 and later inherited Springfield Castle, County Limerick from his father-in-law.
He died in June 1818, aged 72, and was succeeded in his titles by his eldest son John.