Educated at St Paul's School, London, and the Royal Military College, Sandhurst, in 1897 Watson was commissioned into the Green Howards and posted to the regiment's 2nd battalion, then serving in India.

[1] He took part in the Tirah Expedition of 1897–1898 on the North West Frontier, in which he was severely wounded, and saw action again in the Boxer Rebellion of 1900.

[2] Watson was 41 years old, and an Acting Lieutenant-Colonel commanding the 5th Battalion, King's Own Yorkshire Light Infantry (now part of The Rifles) during the First World War when the following deed took place for which he was awarded the VC.

On 28 March 1918 at Rossignol Wood, north of Hebuterne, France, a counter-attack had been made against the enemy position which at first achieved its object, but as they were holding out in two improvised strong-points, Lieutenant Colonel Watson saw that immediate action was necessary and he led his remaining small reserve to the attack, organising bombing parties and leading attacks under intense fire.

[5] He is remembered at the CWGC Cemetery at Arras, France and listed under the Middlesex Hussars (Yeomanry); his parent unit.