Kimball was admitted to the Montana State Bar in 1978 and the California State Bar in 1984. He began by serving in the Army as a judge advocate for seven years. In 1986 he decided to leave active service and moved to the Sacramento area. He has now worked as an appellate practitioner in California for over nine years, specializing in appeals, writs and complex law and motion. Kimball regularly appears in the Courts of Appeal throughout the State and is experienced as well in practice before the California Supreme Court and the Ninth Circuit Court of Appeals.