He was the son of William Henry Ashurst (1792-1855) and the father of Emile Venturi.
Ashurst went into partnership with his father as a solicitor in January 1843; from 1855-1862 he was a partner of John Morris, and from 1862-1879 was the Solicitor to the Post Office. He was an Under Sheriff of London and Common Councilman. He published pamphlets advocating reforms in the City of London and in the Court of Aldermen.
He was a friend of Whistler and his mother Anna Matilda Whistler. He was also a friend of Garibaldi and Mazzini, and of Robert Owen, a defender of Chartists and radicals, an advocate for the emancipation of women and for the subject nationalities of Europe.
He was also a member of the Reform Club and a member of The Arts Club from 1873-1885.
Brief Record of the life of William Henry Ashurst in Mr Morris' 80th birthday celebration, privately printed, London, 1904; Boase, Frederic, Modern English biography: containing many thousand concise memoirs of persons who have died during the years 1851-1900 ... Truro, 1892-1921; Hammond, J. L. and Barbara Hammond, James Stensfield, A Victorian Champion of Sex Equality, London, New York and Toronto, 1932.