CJ Williams grew up in Mount Pleasant, Iowa. His father was a haberdasher, his mother a newspaper reporter and editor. He went on to earn undergraduate and law degrees with high honors from the University of Iowa, and a decade later a Masters of Law degree from the University of Missouri. Out of law school, CJ clerked for a federal judge, served as a prosecutor in the Narcotics and Dangerous Drug Section of the Department of Justice in Washington, D.C., in private practice in a large Kansas City law firm, and for almost 20 years as a federal prosecutor in Iowa. In 2016, he was appointed as a United States Magistrate Judge, and in 2018 the President of the United States nominated and the Senate confirmed him as a United States District Court Judge.
He has authored 19 academic articles, and six books, with the seventh scheduled to be published in 2025.