The ARU was formed on 31 December 1906 and marked the fulfilment of Lieutenant J. E. C. "Birdie" Partridge's (Welch Regiment) idea to have a body to administer the playing of rugby union in the British Army.

[1] Shortly after the ARU was formed the RFU donated the Army Cup, which was to be competed for at inter-unit level.

In 1920 the Army–Navy competition was expanded to include the Royal Air Force, the same year that CSM C. W. Jones (Welch Regiment) was to become the first "other rank" to be picked to represent the army.

Between the wars (1920–39) the ARU arranged matches against the French Army, the last of which was played shortly before the Nazi German invasion of France in 1940.

An international team was formed shortly after the end of World War II, known as the British Empire Forces, who played a series of games against France.

Also on a national front the ARU can boast of the fact that it has had appointed from its ranks Presidents for the English and Scottish RFUs.

In September 2011 the Army Senior XV travelled to Australia to participate in the first ever International Defence Rugby World Cup.

In Nov 2010 LCpl Jane Leonard (Royal Engineers) won international honours with England Women playing and winning her first cap against New Zealand at Twickenham.

In 2000 that changed after Army XV players were used to help the England national team prepare for the IRB Sevens.