Bentley Lyonel John Tollemache was the grandson of Wilbraham Tollemache, 2nd Baron Tollemache of Helmingham Hall, Suffolk, and Peckforton Castle, Cheshire, succeeding him to the barony in December 1904, and to the ownership of 35,726 acres (145 km2) of land within Suffolk, Cheshire, Denbigh and Flint.
He was educated at Eton College, and later became a Deputy Lieutenant and a Justice of the Peace.
On 21 August 1901 Tollemache was commissioned a Second Lieutenant in the 3rd (Militia) Battalion of the King"s Own Scottish Borderers, serving in the Second Boer War. He returned from South Africa in June 1902. and was battalion captain in 1905-1906. He also served as a Lieutenant commander in the Royal Naval Reserve.
In 1906-1908 he became a captain in the 3rd Battalion Cheshire Regiment, and was later wounded in the First World War, during which, in 1916, he became a captain in the Royal Garrison Artillery.
