Mills was born in Beardstown and grew up in Jacksonville, staying close to home to attend Illinois College. He was a debater and orator, and a member of Phi Alpha Literary Society. He stayed connected to his alma mater throughout his life, serving on the Illinois College Board of Trustees for 16 years and offering mentorship to many IC alumni. He also served as an Alumni Trustee from 1978 to 1983, received the Distinguished Service Award by the Alumni Association in 1976 and was selected
as Homecoming Parade Marshal in 2012. In 2007, he established the Judge Richard Mills Endowed Scholarship to support IC students with career ambitions to practice law.

Mills earned a Juris Doctor degree from Mercer University in Macon, Georgia, and a Master of Laws from the University of Virginia. After being admitted to the bar, Mills
went on to a long career as an attorney and judge, most recently serving as a United States District Judge for the Central District of Illinois from 1985 until his retirement in September 2022.

Mills proudly followed in family footsteps in both service to the law and in the United States armed forces. He retired as a colonel in the U.S. Army after a 33-year career in active and reserve duty. He was a Korean War veteran and received a Bronze Star, among several other decorations, for his service.

Mills was preceded in death by his beloved wife, Rachel Keagle Mills. The couple married in 1962 and had two sons, Jon and Daniel. He is also survived by three grandchildren and one great-grandchild.