The son of William Thomson, he was born at Moss Side in Manchester.[1] He was educated firstly at Reverend E. W. Hobson's school in Southport, before attending Fettes College in Edinburgh.[1] After leaving Fettes, he decided on a career in the army and attended the Royal Military College, Sandhurst.[1] He graduated from Sandhurst in October 1893, entering into the Royal Munster Fusiliers as a second lieutenant.[2] He was promoted to the rank of lieutenant in February 1896,[3] and served as the adjutant of the 2nd battalion from 1899 to 1903.[1] He was promoted to the rank of captain in July 1901.[4] Thomson served with his battalion in the Second Boer War and was present during operations in the Transvaal,[1] for which he was mentioned in dispatches in July 1902.[5] After the end of the war that month, Thomson left South Africa with other men of his battalion on the SS Orient in October 1902, and was stationed in Ireland.[6] He later returned to South Africa and served as a staff captain for the Pretoria sub-district from March 1906 to June 1909.[1][7]
He was promoted to the rank of major in March 1912,[8] while in May 1912 he was made a brigade-major and seconded to the Middlesex Infantry Brigade.[1] In July of the same year he appeared in a Minor Counties Championship match for Wiltshire.[9] He made his debut in first-class cricket for the Marylebone Cricket Club (MCC) against Kent at Lord's in May 1913.[10] He appeared in two further first-class fixtures in 1913, playing for the MCC against Hampshire and for the Free Foresters against Oxford University.[10] He made three further first-class appearances in 1914, playing twice for the MCC against Yorkshire and Hampshire, as well as appearing for the British Army cricket team against Cambridge University at Fenner's.[10] In six first-class matches, Thomson scored 201 runs at an average of 18.27, with a high score of 53.[11]
At the start of the First World War in July 1914, he was still serving with the Middlesex Infantry Brigade, but returned to the Royal Munster Fusiliers in October 1914.[1] He was killed in action on 21 December 1914, while leading an attack on German trenches at Festubert in France.[1] His body was not recovered from the battlefield and he was later commemorated at the Le Touret Memorial.[1]