Dennis Kessler and his brother Laurence co-own Kessler Group, Inc. He also is a part-time professor at the University of Rochester Simon Graduate School of Business. He is a member of several volunteer boards, including that of the Univertisy of Rochester medical center.

Kessler graduated from City University of New York and earned a master's degree in sociology from John Hay College of Criminal Justice. He also attended Yale University Law School and Northwestern University School of Law.