Shortly after the outbreak of
World War I, Baillon volunteered for service with the
British Army and was
commissioned as an officer into the
South Staffordshire Regiment on 30 January 1915. As Adjutant during the advance through Abancourt on the afternoon of 9 October 1918, he frequently, under heavy fire, proceeded in advance of the battalion in order to find the route. Both before and after this event he carried out his duties regardless of his personal safety under the most adverse conditions, and often under heavy artillery fire. Baillon remained with the South Staffordshires during the
interwar period until 1931, as
adjutant or as a
staff captain. From 1931 to 1932 he was in England, where he attended the
Staff College, Camberley, where
Brian Horrocks,
Sidney Kirkman,
Arthur Dowler,
Cameron Nicholson and
Nevil Brownjohn were among his classmates. From 1936 and 1945, he was employed as a General Staff Officer in the Middle East, Australia and Britain. In 1948 he was made a
Companion of the Order of the Bath. He retired from the Army on 30 March 1949 as a Major-General. From 1949, Baillon was a Director of the Irish brewers,
Beamish and Crawford Ltd, of
Cork. Joseph Baillon died on 11 April 1951. ==Honours and awards==