Mark J. O'Brien Esquire

Mark J. O'Brien Esquire

Tampa, Florida

How long have you been an attorney?

Although it seems like just yesterday that I started my legal career, I am quickly approaching two decades as an attorney. They say that time flies when you love what you do and I certainly love what I do. Having been both a Miami prosecutor and a large firm defense practitioner, I made the decision nearly sixteen years ago to combine my different legal experiences to form a countrywide federal and statewide state criminal defense law firm. Over the course of my two decades as an attorney, I have handled many of the most complex state and federal criminal cases in the State of Florida, the Commonwealth of Massachusetts and in federal courts all over the country. I understand and appreciate what is at stake when someone hires me.

What makes you different from other attorneys?

My experience and training as a lawyer. I began my career in the late 1990's as a prosecutor with the Office of the Miami-Dade County State Attorney. Over 4,000 law students from across the country applied to be a Miami prosecutor yet only 44 of those 4,000 were hired. I was one of those 44. Like all young and inexperienced lawyers, I started at the bottom and worked my way to the top. It was an incredible experience. And I assure you that by the time I left Miami to enter private practice in 2001, I was no longer a young and inexperienced lawyer. I was older, wiser and very well trained. While in Miami, I ran a judicial division on a day-to-day basis. I supervised and trained new prosecutors. Most importantly, I tried a lot of jury trials and defended a plethora of motions. My goal was to learn to prosecute a criminal case so I could later defend a criminal case.

What was it like being a prosecutor in Miami?

Nothing in this world prepares a person to be an attorney like battling day in and day out with the judges, juries and attorneys of Miami-Dade County, Florida. Much like Miami itself, being a prosecutor in Miami-Dade County is unlike anything else in the world. And unlike many big city prosecutorial offices, I tried my first case two weeks into the job. I tried my second case a few weeks later and so on. I was not hired to sit second chair next to a sixty-year old guy during jury trials. And I was not hired to conduct legal research in some windowless library. I was hired to try cases. As a young lawyer in Miami you are thrown into the ocean with the sharks and you either sink or you swim. I most definitely swam. By the time I left I had handled everything from homicides to armed drug trafficking cases along with everything in between. I left the office because there was nothing left for me to accomplish as a prosecutor. And I had no intention of being a life long prosecutor. I wanted to be a criminal defense attorney.

What state bar exams have you passed?

Two. I am a member of the bars of the Commonwealth of Massachusetts and the State of Florida. The summer after I graduated law school I simultaneously, and on my first attempt, passed the bar exams of the Commonwealth of Massachusetts and the State of Florida. Those two bar exams amounted to three straight eight hour days of testing in two different states. I finished the Florida bar exam at 5:00 pm and flew that same night to Boston, Massachusetts to take the Massachusetts bar exam the next morning. So when I say took and passed the Massachusetts and Florida Bar Exams simultaneously I literally mean that I took and passed them simultaneously - with the help of an airplane of course.

What federal bars do you belong to?

I am a member of numerous federal courts, including the Supreme Court of the United States, the United States Court of Appeals for the Eleventh Circuit, the United States Court of Appeals for the First Circuit, the United States District Court for the Southern District of Florida, the United States District Court for the Middle District of Florida, the United States District Court for the Northern District of Florida, the United States District Court for Massachusetts, and the Western District of Texas. I have also been admitted to practice law pro hac vice in the United States District Court for the Eastern District of Washington, the United States District Court for the Eastern District of Kentucky, the United States District Court for the Southern District of West Virginia and the United States District Court for the Southern District of Mississippi. So while my practice is largely limited to the State of Florida and the Commonwealth of Massachusetts, I have litigated federal and state criminal cases throughout the country. My caseload has taken me from the west coast to the east coast to the heartland of America. The bottom line is that if you need me I will fight for you anywhere.

So where are you from?

I was born in New York. I am a proud graduate of the small Catholic private school, Siena College. I went to law school and interned at various prosecutors' offices in and around Philadelphia, Pennsylvania. After graduation I immediately moved to Miami, Florida to start my law career as a prosecutor. In 2001 I left Miami after being recruited by a sitting criminal court circuit judge who presided over my last jury trial as a prosecutor to help start the Tampa office of a Miami defense litigation law firm that was expanding throughout the State of Florida. After a few years working with and learning from this law firm, I decided to combine the positive aspects of all my previous legal jobs to form my own law firm. My goal was to create an honest, hardworking, innovative and aggressive criminal defense law firm that was solely about the practice of law and not at all about the money. I believed then and I still believe now that if I focused on my work, the business will ultimately follow. I have been proven correct over time. I have represented several NFL athletes, MLB players, Olympic athletes, doctors, lawyers, accountants, entertainment figures, police officers, career offenders and first-time offenders.

Have you won anything?

I have won federal jury trials, state jury trials, federal motions to dismiss and federal motions to suppress and state motions to dismiss and state motions to suppress. I have won federal and state appeals and federal and state post-convictions motions. I have obtained federal and state case dismissals. Most importantly I have made private problems for people disappear before they ever became public problems for people. I have represented people that you have never heard of and people that you know by name. My criminal cases have been covered in print and on-line by ESPN, the New York Times, the Boston Globe, the Washington Post, the Los Angeles Times, the San Francisco Chronicle, the Chicago Tribune, the USA TODAY, and nearly all of the local Florida newspapers including the Miami Herald, the Tampa Bay Times (formerly the St. Pete Times) and the Tampa Tribune. A few years ago I even provided legal commentary on criminal cases that I was not the attorney of record for to the media until I realized it is absolutely ridiculous for lawyers to speak publically on criminal cases they are not handling - and thus know little to nothing about. I am here to help solve legal problems for my clients. It follows therefore that if you are not my client and you have a legal problem that I will not comment for sport or ego on television or in the newspapers. This is your life. And I respect how difficult your life is made by criminal allegations. I am here to help you not hurt you. Many of my clients' cases have been considered high profile and thus heavily covered in the news media. I know how difficult that can be for a person.

Why did you start your own law firm?

I started my law firm with one computer in a 175 square foot office with zero windows in 2003. I had no idea if it was raining until I stepped outside the building without an umbrella. Now I work each day in a 3,000 square foot, modern, glass enclosed and technologically well-equipped office with a just a few more than zero windows. I have private investigators, a sentencing specialist and mental health and physical health doctors at my disposal when it is necessary and advantageous for my clients. Most importantly, I have personally trained a team of lawyers that I feel are unlike any other criminal defense law firm's lawyers. Unlike other firms, each of my lawyers worked for me while they were law students. As a result I trained each of them the same way I was trained almost two decades ago. I was not easy on them because I learned many years ago that the criminal justice system is not easy on you, our clients. As a result, our lawyers are smart, tough and aggressive. We take what we do very seriously. We know the stakes. Therefore, we do not golf. We do not sail boats. We do not take long lunches or take early dinners. We do one thing and one thing only. We wake up each day very early and end each day very late with one goal and one purpose: you.

Areas of Practice

  • Criminal Defense
  • Federal Criminal Defense
  • Federal Criminal Appeals and Post-Conviction Motions
  • State Criminal Defense
  • State Criminal Appeals and Post-Conviction Motions
  • White Collar Criminal Defense
  • Mortgage Fraud Criminal Defense
  • Securities Fraud Criminal Defense

Litigation Percentage

  • 100% of Practice Devoted to Litigation

Bar Admissions

  • Florida, 1998
  • Massachusetts, 1998
  • U.S. District Court Middle District of Florida, 2002
  • U.S. District Court Northern District of Florida, 2008
  • U.S. District Court Southern District of Florida, 2013
  • U.S. District Court District of Massachusetts, 2003
  • U.S. Court of Appeals 1st Circuit, 2002
  • U.S. Court of Appeals 11th Circuit, 2003
  • Supreme Court of the United States of America, 2010
  • U.S. District Court Western District of Texas, 2015
  • U.S. District Court Eastern District of Arkansas, 2017
  • U.S. Court of Appeals 2nd Circuit, 2017

Published Works

  • "Strategies For Defending Identity Theft Cases", Aspatore, 2012

Representative Cases

  • Hulk Hogan v. Gawker Media, LLC (represented non-party witness Bubba the Love Sponge)
  • Florida Bar v. Adam Filthaut (prominent trial attorney accused of DUI setup in Bubba/MJ trial)
  • United States v. Jeanette Hevel (former Tampa Police Department Captain)
  • United States v. John Wilson (former Washington Redskin NFL player)
  • United States v. Rashia Wilson (IRS fraud)
  • United States v. Robert Blango (notorious Fort Myers bank robber)
  • United States v. Senad Djedovik (infamous Norwegian Cruse Lines employee)
  • State of Florida v. Rougned Odor (current Texas Ranger MLB player)
  • State of Florida v. Jerramy Stevens 1 (former Tampa Bay Buccaneer NFL player)
  • State of Florida v. Jerramy Stevens 2 (former Tampa Bay Buccaneer NFL player)
  • State of Florida v. Jerramy Stevens 3 (former Tampa Bay Buccaneer NFL player)
  • State of Florida v. Matthew Buendia (former United States Marine charged with shooting a police officer)
  • State of Florida v. Mary Lynn Vu (teacher accused of having sex with her student)


  • Lecturer, Trial Advocacy Skills, Intensive Trial Advocacy Program (ITAP)

Professional Associations and Memberships

  • American Association for Justice, Member
  • National Association of Criminal Defense Lawyers, Member
  • Florida Association of Criminal Defense Lawyers, Member
  • Florida Bar Association, Member
  • Federal Bar Association, Member

Past Employment Positions

  • Office of the Miami-Dade County State Attorney


  • English (Primary)
  • Spanish