A nationally recognized authority on criminal punishment, Professor O'Hear teaches criminal law and related courses. He is an editor of the Federal Sentencing Reporter and the author of more than sixty scholarly articles, books, and book chapters on sentencing, criminal procedure, and other legal topics. His books include The Failure of Sentencing Reform and Wisconsin Sentencing in the Tough-on-Crime Era: How Judges Retained Power and Why Mass Incarceration Happened Anyway.
Professor O'Hear is a graduate of Yale College and Yale Law School, where he was editor-in-chief of the Yale Journal of Law & the Humanities and an editor of the Yale Law Journal. Following law school, he clerked for United States District Court Judge Janet Bond Arterton in New Haven, Connecticut. He then practiced civil and criminal litigation at Sonnenschein Nath & Rosenthal in Chicago. He joined the Marquette Law School faculty in 2000, and served as the Law School's first Associate Dean for Research from 2008 to 2015.
Professor O'Hear was a member of the Milwaukee Fire and Police Commission from 2010 to 2016. In 2015-2016, he directed the Marquette Clemency Workshop, which provided legal assistance to federal prisoners seeking clemency from President Obama. Since 2017, he has co-chaired a committee of the Wisconsin State Bar that is examining mass incarceration and racially disparate incarceration in the state. His current scholarly research, which focuses on the sentencing of individuals convicted of violent offenses, is supported by a grant from the Charles Koch Foundation.
Professor O'Hear has been awarded the Robert W. Warren Public Service Award by the Eastern District of Wisconsin Bar Association, and is an elected member of the American Law Institute.