Mark J. O'Brien

Mark J. O'Brien, founder of O'Brien Hatfield, PA, leads a distinguished career in federal criminal defense. With over 25 years of experience, he represents clients in federal criminal courts both in Florida and nationwide. Previously serving as a Miami prosecutor, Mark is now recognized by federal judges and prosecutors as a leading defense attorney. His extensive practice often sees him traveling, maintaining a commitment to each case as if it were his first.

Mark began his legal journey in the late 1990s as a prosecutor in Miami, Florida. In 2002, he established his own firm, driven by professional insights gained throughout his career. His practice blends traditional values with innovative strategies to defend those accused of federal crimes.

From 2002 to 2012, Mark focused on defending individuals and corporations in federal courts throughout Florida. Since 2012, he has expanded his practice to federal courts nationwide, building a reputation for success in numerous high-profile cases.

Mark's achievements include recognition as a Top 100 Trial Lawyer and a Super Lawyer, underscoring his expertise and dedication to his clients.