Rupert Downes was born at Mitcham, South Australia, on 10 February 1885, the son of Major General Francis Downes, a Crimean War veteran. Rupert studied medicine at Ormond College in Melbourne, where he gained his Master's Degree in surgery in 1912. As a young man Downes joined the Victorian Horse Artillery as a trumpeter before being commissioned as a captain in the Australian Army Medical Corps in 1908.
With the outbreak of war in 1914, Downes volunteered for the Australian Imperial Force. He was given command of the 2nd Light Horse Field Ambulance (LHFA) and promoted to Lieutenant Colonel; however when he went to Gallipoli, it was with the 3rd LHFA.
Downes also wrote frequently to his wife, Doris, usually signing off with 'Adieu my dearest wife' or 'Adieu my sweet one'. In an unusual occurrence, Doris was able to visit her husband in Egypt for a few months in early 1917. Returning to Australia, now pregnant with their second daughter, Doris's ship struck a mine and sank in the Indian Ocean. Luckily, she and most of the other passengers were rescued.
After Gallipoli, Downes served the remainder of the war in the Sinai-Palestine theatre, achieving ever higher positions with the Light Horse medical services throughout that campaign. In 1916 he became Assistant Director Medical Services for the Anzac Mounted Division. By 1917 he was Deputy Director of Medical Services (DDMS) for Chauvel's Desert Mounted Corps and by April 1918 he had become DDMS Egypt. For his outstanding service, Downes was appointed CMG in January 1918, and throughout the war was also mentioned in despatches several times.
During the war Downes made many innovations. These included:
. Introducing a sand sledge for transporting the wounded, as movement by camel was uncomfortable.
. Making the Field Ambulance units more mobile, including creating a mobile surgical unit.
. Creating a field laboratory to combat malaria ( which was particularly bad in the Jordan Valley).
Following the war, Downes returned to his private medical practice in Melbourne, where he was also Honorary Surgeon at several hospitals, including Prince Henry. In 1927 he was a Foundation Fellow of the College of Surgeons of Australasia (later RACS). During this time Downes continued to serve the military medical services at home as well. In 1934 he became Director General Medical Services and achieved the rank of his father, Major General.

With the outbreak of the second war, Downes continued to serve and innovate. Holding several senior military medical posts in Australia, he made many achievements. They include:

. Pressing for the building of large military hospitals in the state capitals ( which became the repat hospitals, such as Concord and Heidelberg etc).
. Introducing the recording of blood groups on soldiers' dog tags.
. Introducing inoculation against tetanus, smallpox, typhoid and paratyphoid fevers.
. Developing women's services such as the Voluntary Aid Detachments.

With the end of the war in sight, Downes turned 60 and retired from his duties. He was immediately invited to write the official medical history of Australia in the Second World War (he had previously contributed a chapter to the First World War Official History) which he accepted. But on 5 March 1945, he and Major General George Vasey were flying from Cairns bound for New Guinea, when the aircraft crashed shortly after take-off, killing all aboard. Major General Rupert Downes is remembered on the Commemorative Roll.