He was born in 1698,[1] the son of Rear-Admiral Sir Thomas Dilkes and his wife Lady Mary, daughter of Murrough O'Brien, 1st Earl of Inchiquin and widow of Henry Boyle of Castlemartyr.
[10] Dilkes held the posts of Quartermaster-General and Barrack-Master-General of the Forces in Ireland,[3][11] but after voting alongside his half-brother Henry Boyle against the government in the Money Bill dispute in December 1753[11] he was deprived of his offices.
[16] In about 1760 he attempted to convert the cemetery at Bully's Acre into a botanic garden for the Hospital, but the project was abandoned after the men of the Liberties rioted in protest.
[1] On 16 October 1734 Dilkes had married Anne, daughter of Duncan Cummin MD; he was survived by their children Thomas, Henry, John and Mary.
[3] The eldest son, Thomas, was serving in America as major of the 49th Regiment of Foot, but the "considerable pecuniary disappointments" he experienced on his father's death obliged him to sell out.