Charles N. Gregory earned his bachelor's and legal degrees from University of Wisconsin. After many years in private practice in Wisconsin, he became associate dean of the University of Wisconsin Law School in 1894, serving until 1901. In 1901, he became dean of University of Iowa College of Law, and served in that position until 1911. As dean, he oversaw the introduction of the new three-year course of instruction, as well as the law school's move from the Old Capitol building to a dedicated law building.
He left Iowa for George Washington University Law School, where he served as dean until 1914. His work focused on international law. He died in 1932.