Penrhyn was educated at Eton and the Royal Military College, Sandhurst, before joining the 60th Rifles in 1929.
He served in India and Burma before working with the Free French forces in North Africa during the Second World War.
After the war, he stayed on in Germany until 1948 and spent the rest of his military career training soldiers to fire rifles accurately.
His father was 101 years and 74 days when he died on 3 February 1967 and was then the oldest ever hereditary peer, a record that was not surpassed until the death of the seventh Viscount St Vincent in September 2006.
After Lord Penhryn too died without male issue (he had two daughters), the Penrhyn barony passed to his nephew.