Born in Ballarat, Victoria and a Telephone Mechanic by trade, Edgar Costelloe was 25 years and single when enlisted on the 21st of March 1916 in the 39th Battalion, A Company, Australian Imperial Force, with the rank of Private, Number 77. His Unit embarked from Melbourne, Victoria, on board HMAT A11 'Ascanius' on the 27th of May 1916. Private admitted sick to Hospital, France on the 4th of July 1917; admitted to Hospital, Cheltenham, England to 2nd Southern General Hospital, Bristol- gunshot wound Neck on the 30th of August 1918; injured accidently field on the 27th of August 1918. Returned to Australia per City of York ex England on the 14th of January 1918. Discharged from the 3rd Military District on the 6th of April 1919. Tree No. 2279