Meet the U.S. Attorney

Hayden O’Byrne
United States Attorney

Hayden O’Byrne is the United States Attorney for the Southern District of Florida, appointed by Acting United States Attorney General James McHenry III.  O’Byrne was sworn into the position on January 28, 2025, by Chief United States District Judge Cecilia M. Altonaga.  

Prior to his appointment, O’Byrne served as an assistant United States Attorney in Miami, prosecuting a range of cases – from transnational human, narcotics, and firearms trafficking to alien smuggling and white-collar matters.  In recent years, O’Byrne focused on prosecuting complex victim-centered crimes, including gang-related violence and fraud.

Before joining the Department of Justice, O’Byrne worked as an associate attorney in the Miami office of K&L Gates, where he handled trademark, fraud, product liability, employment, and other civil matters, including multi-district class action litigation.

O’Byrne received his law degree and a bachelor’s degree in history and political science from the University of Miami, in Coral Gables, Florida.