After leaving parliament, Hanson replaced Sir Charles Cooper as Chief Justice of the Supreme Court of South Australia in 1861. He was knighted in 1869 by Queen Victoria when he visited England, and was acting Governor of South Australia for 1872–73. In his spare time Hanson gave much time to theological studies. His publications include "Law in Nature and Other Papers" (1865), "The Jesus of History" (1869), "Letters to and from Rome" (1869), "The Apostle Paul", and the "Preaching of Christianity in the Primitive Church (1875)".