Background
He was the fourth son of Frederic Thesiger, 2nd Baron Chelmsford and his wife Adria Fanny Heath, daughter of Major-General John Coussamker Heath.
He was the fourth son of Frederic Thesiger, 2nd Baron Chelmsford and his wife Adria Fanny Heath, daughter of Major-General John Coussamker Heath.
Thesiger was educated at Winchester College and in 1884, he was nominated Page of Honour to the Queen, a post he fulfilled for the following six years.
In 1893, he became a Staff Commissioner of Police. Thesiger joined the Imperial Yeomanry as private during the Boer War. In 1900, he was advanced to a lieutenant, and on 1 November 1901 he became Captain of the 15th Battalion (Imperial Yemoanry) with the temporary rank of Captain.
In 1902 he became a second lieutenant of the Surrey Yeomanry.
He was transferred as major from the Yeomanry into the Territorial Force in 1908. In the First World War Thesiger was wounded twice and was mentioned in despatches as many times.
He was appointed to the 10th Battalion, Royal West Surrey Regiment in 1917, commanding it until 1918, and subsequently the 10th Battalion, Royal West Kent Regiment for another year. He retired from the Territorial Army in 1929, having reached the age limit.
She died in 1922, and Thesiger remarried Sydney Hilda Hutton-Croft, daughter of George Arthur Hutton-Croft on 3 October 1929, but she died only a year later.