Career
As an exchange troop leader O'Donnell served with 1st King's Dragoon Guards and was dispatched as part of the British Army response to the Malayan Emergency in 1957. He was posted to the 3rd Cavalry Regiment and, as a major, was deployed to Vietnam where he was Mentioned in Despatches. In retirement he became Chairman of a campaign to build a permanent monument in Canberra to commemorate the contributions of migrants to Australia.
In 2000 he shot for Australia at Bisley.