Will was born in Lafayette, Louisiana in 1948 to William P. Mills, II and Dorothy Olivier Mills. He attended Cathedral High School and received his Bachelors in Wildlife Management and a Master's degree in Fisheries Biology from The University of Southwestern Louisiana. He began his career as an Independent Landman and formed WPM Exploration, Inc., in 1978. In 1990 he formed MPW Properties, L.L.C., a real estate investment company. Today Mr. Mills continues as President of both companies and owns numerous properties throughout Louisiana, Virginia, California, Alabama, Florida and Texas.

He is very active in the Republican Party and has served as Finance Chairman and Treasurer of the Republican Party of Louisiana. He currently serves on the State Central Committee. He has served as Vice President and executive committee member of the Independent Petroleum Association of America (IPAA). Mr. Mills actively lobbies in Washington DC for the Oil & Gas Industry and has served on the Board of Directors of the Louisiana Independent Oil & Gas Association (LIOGA) now known as LOGA.

Mr. Mills sits on the Boards of The Stuller Family Foundation and is Founding Member of The Mills' Family Foundation. He has also funded the David Caffery Mills Memorial Scholarship at the University of Louisiana at Lafayette. He is co-founder and past Board Member for the Acadiana Crisis Pregnancy Center in Lafayette. He is a member of the Republican Governor's Association and the Council for National Policy (CNP).

He and his wife Sandra are the parents of six children.