Sullivan is a graduate of Harvard Law School as well as Morehouse. He is a leading theorist in the areas of criminal law, criminal procedure, trial practice and techniques, legal ethics, and race theory. He is the faculty director of the Harvard Criminal Justice Institute and the Harvard Trial Advocacy Workshop. Professor Sullivan also serves as Faculty Dean (formerly, “Master”) of Winthrop House at Harvard College. In 2009, he became the first African American ever appointed Master in Harvard's history.  The Huffington Post dubbed him “The Man Who Dealt the Biggest Blow to Mass Incarceration,” noting that several media reported that Professor Sullivan won the release of more wrongfully incarcerated persons – over 6000 – than anyone in U.S. history. Prior to joining Harvard’s faculty, Professor Sullivan was on the Yale Law School faculty where he won the award for outstanding teaching after his first year.  Before joining the legal academy, he served as the Director of the Public Defender Service for the District of Columbia. He also spent several years in private practice in two major Washington, D.C. law firms where he specialized in white-collar criminal defense and complex commercial litigation.