Born William Carrington, he was the second son of Robert Carrington, 2nd Baron Carrington, and his second wife the Hon. Charlotte Drummond-Burrell, daughter of Peter Drummond-Burrell, 22nd Baron Willoughby de Eresby. He and his two brothers assumed by royal licence the surname of Carington in 1880. He was educated at Eton and served in the Grenadier Guards, achieving the rank of Lieutenant-Colonel. He fought in the Egyptian Campaign of 1882 and was awarded a medal for his actions.