Benson was born in Alresford, Hampshire, the son of William Benson, a barrister, and Elizabeth Soulsby Smith. He was educated at Winchester and Balliol College, Oxford. He graduated in 1887, and would later become a philosophy lecturer at Balliol.
He was involved in politics and represented Woodstock in the House of Commons from 1892 to 1895 and served as Mayor of Lichfield between 1909 and 1911. In the latter year Benson was raised to the peerage as Baron Charnwood, of Castle Donington in the County of Leicester.