Ford joined the Supreme Court of Illinois as an associate justice in February 1841, as the Democratic-majority legislature increased that bench to nine members (from four). The other new justices were former U.S. Senator Sidney Breese, future U.S. Senator Stephen A. Douglas, Walter B. Scates and Samuel H. Treat. Upon agreement with his colleagues, Ford was assigned circuit duties on the northern circuit and moved to Oregon in Ogle County, Illinois, but would ultimately only serve as associate justice on that court for little more than a year.