His research focuses on how the law generates, shapes, and accommodates individual preferences in its regulation of intimate relationships and the family. His recent work in the area has focused on the role of choice in the design of state marriage policy as well as the use and limits of private agreements. Professor Matsumura teaches Contracts, Civil Procedure, Family Law, and a seminar on Reproduction and Reproductive Technologies. In 2017, he was awarded the Outstanding Teaching Award by vote of the graduating class.