Private John McCorkell served with the 5th Victorian Mounted Rifles (5th VMR) in the Boer War in South Africa during 1901-1902.

McCorkell embarked on the 'Argus' on 15 February 1901, and disembarked at Port Elizabeth in March 1901. While entraining in Port Elizabeth, McCorkell suffered his first bout of illness. Following recovery, he re-joined the 5th Victorian Mounted Rifles, which was proceeding through Cape Colony and Orange River Colony to Pretoria, where the regiment was mobilized between 24 March and 4 April, 1901. McCorkell served in places such as Wakkerstroom, Bronkhorstspruit, Pretoria, Colenso, Ladysmith, Vryheid and Buffalo River. Routine activities of the Fifth included expelling Boer families from their farms, capturing their livestock, and assisting other Australian and Imperial units in large operations against Boer commando groups.

Throughout 1901, McCorkell and his unit travelled almost daily, trekking through harsh conditions. Sudden changes of operational orders often caused confusion for units and led to additional gruelling night marches. Camping conditions were very basic, with disease easily spread.

In December 1901, the 5th Victorian Mounted Rifles moved to the Transvaal town of Wakkerstroom, for operations and supply renewal, but also to join other Australian and British Empire units for Christmas. McCorkell died there of enteric fever on 21 January 1902.