The Military Medal was created in 1916 for other ranks in the Army to correspond with the Military Cross , which was intended for lower ranking Army officers (Captain or less) and Warrant Officers. The Military Medal was awarded to other ranks for 'acts of gallantry and devotion to duty under fire'.

In 1916, the Medal was extended to other ranks of the Navy serving in France, but only for actions in World War 1. In 1931, the availability of the Medal was extended to other ranks of the Air Force for gallant conduct on the ground.

The Medal was discontinued in 1993 when the Military Cross was made available to all ranks.

Source:
Australian Honours List