He was the son of Henry Winthrop O'Donovan, The O'Donovan, and Amelia O'Grady, daughter of Gerald de Courcy O'Grady, The O'Grady, and Anne Wise. O'Donovan was a descendant of Donal II O'Donovan, The O'Donovan of Clancahill, the last such to be formally inaugurated in the ancient Gaelic manner, with the White Rod, by the MacCarthy Reagh, Prince of Carbery.
O'Donovan graduated from Magdalen College with a Bachelor of Arts.
His first office, following his accession to the chiefship, was that of High Sheriff of County Cork in 1892. From 1899 to 1902 he fought in the Second Boer War, was at operations in the Transvaal, Orange River Colony, and Cape Colony, and was mentioned in despatches. From 1903 to 1914 O'Donovan was Colonel of the 4th Battalion (Extra Reserve), Royal Munster Fusiliers.
He was also Justice of the Peace and Deputy Lieutenant for County Cork. In 1911 he was invested as a Companion of the Order of the Bath (Civil Division).
