While at Uni, John "Jack" Wills Jr. was active in theatre and music. He was a cast member in the school play for all five years, and sang in the operetta, mixed chorus, and boys’ ensemble. He was a member of the student council during his sophomore year, and served as the editor in chief of the student newspaper for two years.

After graduating, Wills became a scholar of global and Chinese history. He performed meticulous research, diving deep into archives and traveling to various countries to obtain primary and secondary sources in many different languages. His work resulted in incredibly detailed books and articles that painted vivid, complete pictures of his subjects. Wills taught history at the University of Southern California, where he helped introduce East Asian studies to the university’s curriculum. He served as the director of the East Asian Studies Center and chairman of the East Asian Languages and Cultures Department. Even after retiring in 2004, Wills continued researching and publishing works, holding conferences, and mentoring students.