Geoffrey Selwyn Walker (SN 7970/2nd Lt.) born at Ballarat, was 18 when he enlisted in Ballarat on September 30th 1915. On November 8th he embarked aboard the Bakara and sailed to Egypt before being deployed to France in August 1916 to serve as a driver with the Australian Service Corps. In October 1917 he commenced training with the Australian Flying Corps and by April 1918 he graduated as a Flying Officer (pilot) and was commissioned as a 2nd lieutenant. He then developed pulmonary tuberculosis which led to his return to Australia aboard the City of Karachi. He disembarked at Melbourne on October 24th 1918 and his commission was terminated on December 2nd, three weeks after the Armistice was signed.

His brother Edward also served in the AIF and is honoured with a tree in the Avenue.