Gary Banz was born December 7, 1945, in Sylvia, Kansas. He joined the United States Army in June 1968 and served until January 1970. He was awarded the Army Commendation Medal on March 19, 1970. He also served in the United States Army Reserve from December 1982 until September 1990. He was awarded the Army Achievement Medal on May 7, 1985.
Banz married Linda and had three children who graduated from Midwest City High School. Banz taught in various Oklahoma school districts before retiring and eventually running for office. Banz was first elected to House District 101 with no Democratic opposition in 2004. However, he did face two primary opponents, Jeremy Sellers and Todd Dealy. He faced no opposition in 2006 In 2008, he defeated Democratic challenger Donnie Lewis.In 2012, he defeated Democratic challenger Stephen Covert.