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The Criminal Defense Attorney Doctors, Lawyers, Business Executives, Accountants, Federal Agents, Police Officers, Military Members, Professional Athletes, Entertainment Figures, And First Time Offenders Call When They Need A Criminal Defense Attorney.

So Should You.

Top Criminal Attorneys with offices in Tampa, Orlando, and Miami, defending cases in Florida and nationwide

A Trusted Name In Criminal Defense

Firm founder Mark J. O’Brien is a former prosecutor who has handled thousands of criminal cases. Since 2003, O’Brien Hatfield, P.A. has handled hundreds of cases in both federal and state courts.

We have the knowledge and resources to craft tenacious criminal defense strategies, including firm private investigators and medical professional networks.
We understand the potential our work has to change the trajectory of our clients’ lives. That’s why we focus on one thing and one thing only. We wake up each day with one goal and one purpose: you.


Federal Crimes

Federal Crimes

State Crimes

State Crimes

Appeals and Post-Conviction Motions

White Collar Crimes

White Collar Crimes

Drug Crimes

Drug Crimes

Sex Crimes

Sex Crimes

Whistleblower Claims

Whistleblower Claims

Mark J. O’Brien’s cases have been featured in

Many lawyers advertise various awards they have “won” from various websites proclaiming them to be a “Top Lawyer in Florida”, a “Top Attorney Under 40” or a “10.0 Rating”, and so forth. Please note that any attorney who advertises such “awards” has to pay money to the particular website to be granted these “honors”. I refuse to pay for an award or honor. I rely on my experience, my training and results. If you are looking for attorneys who accept paid for “awards” or “honors”, we are not your law firm. However, here is what federal judges across the country are saying about our firm in open court in real cases.

O’Brien Hatfield, P.A. Brand Logo

Read What Judges Are Saying

Federal Magistrate Judge Thomas G. Wilson

“Mr. O’Brien is a very excellent, skilled, experienced lawyer. If you want to go to trial, he’ll go to trial, and guess what, he’s a very competitive lawyer, he wants to win. I can’t think of anybody who could do a better job, whether you want a trial or not. I mean, there’s no one I could think of that would do a better job than Mr. O’Brien.”

United United States v. Algarin,
The Middle District of Florida
Tampa Division
March 6, 2018

Federal District Court Judge James I. Cohn

“Your lawyer did a hell of a job for you. There are not a lot of lawyers that handle sentencing issues as well as your lawyer did in this case. So you owe him a debt of gratitude. He saved you a lot of time.”

United States v. Marcus Lewis
The Southern District of Florida
Fort Lauderdale Division
September 18, 2019

Federal District Court Judge William Jung

“And I'm not an advertising company for Mr. O'Brien's law firm, but in my humble opinion you got a million dollars’ worth of legal talent in this case.”
United States v. Kenyatta Anderson,
July 20 2022

Federal District Court Judge Lisa Godbey Wood

“Mr. O’Brien, Mr. Jackson, come forward. Mr. Jackson, the jury has found that you are not guilty on both charges which you were indicted on. As a result, I now adjudge you no guilty of the offenses and you will be free to leave from these charges. Your attorney did an excellent job in the case and the jury’s verdict will become the record of The Court.”

United States of America v. Andrew Jackson
The Southern District of Georgia
Brunswick Division
January 30, 2019

Federal District Court Judge William Jung

“You have actually, in my humble opinion, probably hired the best lawyer right now in the State of Florida.”

United States v. Jose Andujar,

Federal Magistrate Judge James R. Klindt

“Mr. O’Brien is not afraid to say what he thinks and believes. He is not going to pull any punches in terms of speaking up and representing his client in a vigorous and zealous way.”

United States of America v. Lorenzo Mendez-Ortiz
The Middle District of Florida
Jacksonville Division
August 31, 2018

Federal District Court Judge John Antoon, II

“And you’ve had outstanding counsel here. You found Mr. O’Brien on your own, which worked to your advantage because not every attorney would have spotted the issues that he spotted and communicated to the Court the way he did. But the likelihood of that ever happening again is minuscule.”

United States v. Tralvaster Epps
The Middle District of Florida
Ocala Division
February 15, 2022


Mark J. O'Brien Esquire

Mark J. O’Brien, Esquire

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Victoria E. Hatfield Esquire

Victoria E. Hatfield, Esquire

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Olivia Nathan Attorney

Olivia Goodman, Esquire

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Experienced In Both Federal And State Courts

Our extensive trial experience makes us uniquely prepared to litigate any federal or state criminal case, no matter how complex.

We’ve won favorable verdicts and settlements for all kinds of white collar crime and fraud cases such as health care fraud, mortgage fraud and tax evasion allegations in Florida.

We also defend individuals charged with federal and state drug crimes. Federal courts and the state of Florida aggressively prosecute drug crimes, levying harsh penalties against offenders. Our Hillsborough County criminal defense attorneys represent individuals charged with crimes ranging from conspiracy to committing drug trafficking or importation to possession of marijuana, oxycodone or prescription drugs, and the manufacturing and distribution of methamphetamine throughout Florida.

Attorney Mark J. O'Brien

Mark, thank you for everything. I will forever be indebted to you. You have stood by me and believed in me when it was not the popular thing to do. You are an amazing advocate.

Adam Filthaut

  • Former Partner at the Law Firm of Adams and Diaco (Robert Adams and Stephen Diaco)
  • MJ (Todd Schnitt) Morning Show/Bubba the Love Sponge Clem Trial
  • Phil Campbell DUI Setup/Florida Bar Trial

Client Testimonials

There is absolutely nothing that I can do that would be enough to thank Mark for literally saving my life. As we walked outside of the courthouse, my father in law was so happy and told Mark that, “I have to change your name in my cell phone to JC or Jesus Christ, because you just saved a life, in fact, you just saved the lives of an entire family!”
My family and I are so impressed with Mark’s professionalism, demeanor and energy from that first scary day we met in a federal courthouse in Orlando, Florida to the amazing last day we hugged him goodbye standing outside a federal courthouse in Brunswick, Georgia. Thank you Mark for giving me back my life and making it possible for me to have a future!
Andrew Jackson

In taking my side, and standing by me with enthusiasm, and protecting my wife and child from myself, you’ve done me as great a service as anyone else ever has, even on the battlefield. I know I may never have the opportunity to repay you directly. So the best I can promise you, is that I will move forward as a man, citizen, Marine and father deserving of the service you’ve done me. I will not disgrace it by squandering this second chance.

Again, thank you. You saved my life.

Grady Kurpasi
United States Marine Corps

God put the Best Attorney and human being in the world in my life, one who displayed outstanding professionalism and experience in every court, and in addition to that, never stopped offering his kindness and generosity. That was you, Mark J. O’Brien… Thank you for doing everything possible to make me a free man.

Eduany Cruz Alvarez