A native of Filer, Idaho, Captain Mills is a 1990 University of Arizona graduate with bachelor's degrees in computer science and political science. He earned a Master's of Science in electrical engineering in 1996 and a 2005 Information Systems & Operations graduate certificate from the Naval Postgraduate school. He also is a 2008 graduate of the Naval War College Naval Command and Staff program. A plank owner of the Information Professional Community, he is a fully qualified Surface Warfare Officer, Joint Qualified Officer, and Information Warfare Officer.
In 2016, Captain Mills was appointed an Honorary Chief Petty Officer by MCPON.