During World War I. Burnell served as a Lt Colonel in the London Rifle Brigade and won a DSO in 1918. After the war, he rejoined the family firm of stockbrokers in the City. He was Chairman of the Wokingham Rural District Council for 35 years. In 1954 he was awarded the OBE for public service in Berkshire.
He married Jessie Backhouse Hulke in 1903 in Kensington, London. They had four children and their son Dickie Burnell was also an Olympic rower, winning a gold medal in 1948 in the double sculls.