Mary T. Hannon

MARY HANNON focuses her practice on intellectual property litigation. Her professional background gives her a deep understanding of her clients’ business objectives and IP portfolio development, enabling her to approach each matter with both practical insight and strategic perspective. 

Before law school, Mary worked as a patent agent at a boutique intellectual property law firm in Chicago, where she prepared and prosecuted patents across a variety of industries, particularly in the chemical and materials sciences. She also served as a research chemist at a chemical manufacturing company, developing end-use formulations for agricultural and personal care markets. 

Following law school, Mary clerked for Judge John Z. Lee of the U.S. Court of Appeals for the Seventh Circuit and for Judge Alan D. Lourie of the U.S. Court of Appeals for the Federal Circuit. Prior to joining Sidley, she was a Public Interest Law Initiative Fellow with Chicago Volunteer Legal Services.

In 2021, Mary received the Robert C. Watson Award from the American Intellectual Property Law Association for her scholarship on diversity, equity, and inclusion within IP law. Her work was featured in the World Intellectual Property Review’s 2021 Diversity Magazine, and she was named one of WIPR’s “Diversity Trailblazers” in 2022.

Mary earned her J.D., summa cum laude, from DePaul University College of Law, where she served on the DePaul Law Review and was elected to the Order of the Coif. She received the Robert & Clytia Chambers Patent Law Award in 2020. Mary also holds an M.S., with distinction, and a B.S., magna cum laude, in chemistry from DePaul University. She has served as an adjunct professor at DePaul, teaching undergraduate general and organic chemistry courses.

• The Richard Linn American Inn of Court (2020–Present)
• American Intellectual Property Law Association (2021–Present)