Clarence Brooke was born in 1884, the son of Frederick Brooke, a brewery clerk, and his wife Ada. In 1901 he went to work for Beckett & Co of Leeds, and in 1904 his younger brother Percy also joined the bank.
During the First World War Brooke joined the army. Second Lieutenant Clarence Brooke of the East Yorkshire Regiment was killed in action on the Western Front on 31 March 1918. He was 33 years old and left a widow, Annie. His brother Percy had been killed in action three days earlier.