 On leaving school, Ainsworth joined the family business and worked in it until his father's death in 1833.On 15 August 1815, he married Elizabeth Byrom, a daughter and co-heiress of Ashton Byrom of Fairview, Liverpool, but they had no children.On his father's death Ainsworth inherited the Smithills Hall estate and a large shareholding in the bleach works, but he became an inactive partner in it, preferring the life of a country gentleman.