In September 1939 Bryan re-joined the Army at the outbreak of World War II. He served as an Adjutant with the Manchester Regiment in France during 1940 and was evacuated from Dunkirk alongside his brother Ronnie, being Mentioned in Dispatches during the action. He became an Instructor at the Eastern Command Infantry Company Commanders School with the rank of acting Major. From 1942 he served in the Territorial Army Reserve in a variety of roles for the rest of the war. He gave up his commission in 1949.