Despite being past his athletic prime Donald continued to perform in variety theatres and at Highland games as a judge or in veteran events until 1912. A few years earlier in 1903 Robert Barr invited him to endorse his soft drink 'Iron Brew' using Donald's image on the label with Donald proclaiming 'I can recommend BARR's IRON BREW to all who wish to aspire to athletic fame' signed Donald Dinnie, All-round Champion Athlete of the World.
It is also recorded that during World War I the troops in trenches would crouch as a 16-lb mortar shell whizzed overhead, saying, "There goes another Donald Dinnie". Such was his fame that an Aberdeen artist CJ Beattie painted his portrait which is held by the Scottish National Portrait Gallery in Edinburgh.
In later years Donald was struggling to survive financially and in his 70s was still performing a strongman act in the London theatres. His act was to support a platform made from a large table while two Highlanders danced a "fling" on it. The London authorities eventually withdrew his performing licence due to his advancing years and in consideration for his personal safety. As a result a benefit concert was organised to assist Donald in his old age. All the celebrities of the day turned out to give of their services in honour of the great man and provide him with a small annuity.
The Scots Magazine in August 1937 devoted their cover page commemorating the centenary of Donald Dinnie's birth. More recently (1999) David Webster & Gordon Dinnie chronicled his life in their book aptly titled 'Donald Dinnie The First Sporting Superstar.'