Cator was commissioned a second lieutenant in the Scots Guards on 9 June 1897, and was promoted to lieutenant on 17 May 1899.[1] He served with the 1st battalion of his regiment in South Africa during the Second Boer War, and was present at the battles of Belmont, Modder River, and Magersfontein in 1899. The following year, he took part in the march to Bloemfontein and Pretoria, the battles of Diamond Hill and Belfast, and advance to Komatipoort.[2] Following the end of the war in late May 1902, Cator returned home with his regiment in the SS Tagus, which arrived in Southampton in July.[3]
Cator later served in the First World War and was promoted to brevet lieutenant colonel in June 1916[4] and to brevet colonel "for distinguished service in the Field" a year later.[5] He was then General Officer Commanding 58th (2/1st London) Division, taking part in the Battle of Passchendaele in 1917.[6]
He later reverted to his substantive rank of brevet colonel and took command of a brigade, which saw him promoted to temporary brigadier general while so employed, in February 1919.[7]
He became a substantive major general in June 1925[8] and was Commander of Lucknow District in India in 1927 before becoming General Officer Commanding London District and then being placed on half-pay in May 1931[9] before becoming Major-General Commanding the Brigade of Guards in April 1932.[10][11]
Cator lived at Trewsbury near Cirencester and died in a hunting accident in November 1932.[12]