Elliott won the 1919 federal election as a Nationalist Party of Australia candidate for the Senate, and was re-elected in the 1925 election. His involvement with returned servicemen's issues led to his redrafting of the constitution of the Returned Sailors and Soldiers Imperial League of Australia, and he played an important part in the Victoria Police strike, making a call alongside Lieutenant General Sir John Monash for members of the AIF to come to Melbourne Town Hall and sign up as special constables. In 1926, he was appointed to command the 15th Brigade again, and the following year was finally promoted to the rank of major general, and became the commander of the 3rd Division. Suffering from chronic post-traumatic stress disorder, he committed suicide in March 1931.