Wiltshire had recently been promoted to Captain in the 22nd Battalion when he arrived at Gallipoli in September. Against his wishes he was given an adminstrative role, assisting his senior officer.

Part of Wiltshire's job entailed censoring their letters home to ensure they don’t let slip any classified information.

In June 1917 Wiltshire was promoted lieutenant-colonel and appointed to command the 22nd Battalion. At the age of 26, he was one of the youngest Australian battalion commanders

Wiltshire was awarded the Military Cross in 1917 for his work in commanding his company and his ‘gallant and good conduct’ at Pozieres where he was injured with a gunshot wound in the leg.

In October 1917, Wiltshire received the Distinguished Service Order and mentioned in despatches for his service at Broodseinde, Belgium

After the War, Wiltshire returned to Victoria and his old employer, the Bank of Australasia where he enjoyed a successful career, rising to be Superintendent of the Bank in 1944, then General Manger of the newly merged Australia-New Zealand (ANZ) Bank in 1951