 His father was Sir Ralph Assheton, 1st Baronet (1860–1955), and his mother, Mildred Estelle Sybella Master (1884–1949).He was educated at Summer Fields School and Eton College.Assheton was Member of Parliament (MP) for Rushcliffe from 1934 to 1945, for the City of London from 1945 to 1950, and for Blackburn West from 1950 to 1955.