Born on 17 August 1905, Sir Cyril was the son of Sir Alexander Kleinwort and became Chairman of the family company. He had long associations with the Royal College of Surgeons and was a leading figure, under Lord Kindersley, in arranging the College appeal. His outstanding experience and wisdom in merchant banking and insurance became a great benefit to the College and he was admitted to the Court of Patrons in 1968. Thereafter he continued to help the College and demonstrated how medicine and society can work together. In 1978 a citation was delivered by Walpole Lewin when Sir Cyril was admitted to the Honorary Fellowship of the Royal College of Surgeons. He served in the RNVR during the war as a Lieutenant-Commander. In 1933 he was married to Elizabeth Kathleen Forde and they had three daughters. He listed his hobbies as hunting and yachting. He died on 8 September, 1980.