After 1865, he rented his farm and relocated to Boscobel, Wisconsin, and, in 1873, moved to Madison. He was one of the incorporators of the Oshkosh and Mississippi Railroad Company and the Military Ridge and Grant County Railroad Company. In 1871 he was appointed a regent of the University of Wisconsin, and he served on the State Agricultural Society and was secretary of the State Board of Centennial Managers. In 1875, Field worked to secure the upset victory of Angus Cameron over incumbent Republican Senator Matthew H. Carpenter, with the assistance of Democratic votes in the Wisconsin Legislature.