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Mark Allan Hammer

Criminal defense Attorney at Saint Louis, MO

4.4   13 reviews
  • State Years
    Missouri - MO 14 years
    Minnesota - MN 28 years
    Washington - WA 33 years
    California - CA 36 years
  • Licensed for 14 years
    State MO
    Acquired 2009
    Good Standing, Active No misconduct found
  • Licensed for 28 years
    State MN
    Acquired 1995
    Not Authorized - Non-payment of fees No misconduct found
  • Licensed for 33 years
    State WA
    Acquired 1990
    Administrative Suspension No misconduct found
  • Licensed for 36 years
    State CA
    Acquired 1987
    Not Eligible to Practice Law (Not Entitled) No misconduct found

We have not found any instances of professional misconduct for this lawyer.

About Mark

Learn Mark’s areas of practice.

Practice areas
  1. Criminal defense
    The Hammer Law Firm places an emphasis on complex criminal charges, including federal criminal charges, white collar crimes, violent crimes, felony drug charges, gang-related crimes, weapons offenses and sex crimes. We also offer experienced representation on behalf of clients charged with a DUI/DWI, theft, domestic violence or drug possession charges.

    12 years

  2. DUI and DWI
    If you have been arrested for DUI/DWI in Missouri, do not make the mistake of assuming that drunk driving is just a minor charge. The penalties for drunk driving may include jail time, probation, court ordered alcohol treatment, monetary fines, community service and a driver's license suspension. If you are convicted of drunk driving, you will have a criminal record that could cost you your job or limit your future employment opportunities.

    12 years

  3. Domestic violence
    If you have been arrested for domestic violence, do not take your charges lightly. Do not assume that the prosecution will drop the charges because your wife, husband, girlfriend or boyfriend asks them to drop the charges. The prosecution can, and probably will, proceed with charges with or without the victim's consent. If the alleged victim refuses to cooperate voluntarily, the prosecution can compel the victim to testify through the use of a subpoena.

    12 years

  4. Federal crime
    As a defense attorney, Mr. Hammer puts his knowledge of the law and the system to work for the people he serves. Some of the federal charges handled by attorney Hammer include: White collar crimes: including fraud, embezzlement, identity theft, mail fraud, and many others Criminal conspiracy: including situations dealing with drugs, kidnapping, sex crimes, extortion, and more Drug charges: possession, trafficking, sale or distribution, and manufacturing Violent crimes Sex Crimes

    12 years

  5. White collar crime
    We handle all types of white collar crime allegations, including: Fraud Embezzlement Mail fraud Mortgage fraud Identity theft Securities fraud

    12 years

At our firm, we are innovative and results-oriented. We do not limit ourselves to one single approach or one single philosophy.

When a case requires aggressive action, we are aggressive. When a case requires negotiation, we work to negotiate a beneficial outcome. Through decisive and strategic action, we strive to achieve the best possible results that protect our client's rights, record and freedom.

Prior to becoming a criminal defense lawyer, founding attorney, Mark A. Hammer, spent more than 13 years as a prosecutor, and taught trial advocacy and criminal procedure to police and prosecutors from Seattle to South Carolina. Mr. Hammer's experience as a prosecutor provides each client we serve with a decided advantage when it comes to presenting a criminal defense in state or federal courts. Knowing how law enforcement officers and prosecutors assemble their case and understanding their motivations can be vital if it is necessary to negotiate a plea or push for a full jury trial.

The Hammer Law Firm places an emphasis on complex criminal charges, including federal criminal charges, white collar crimes, violent crimes, felony drug charges, gang-related crimes, weapons offenses and sex crimes. We also offer experienced representation on behalf of clients charged with a DUI/DWI, theft, domestic violence or drug possession charges.

Photos and videos


The Hammer Law Firm, LLC
1430 Washington Avenue.
Suite 325
Saint Louis, MO, 63103
The Hammer Law Firm, LLC
100 Chesterfield Business Pkwy
Suite 200
Chesterfield, MO, 63005
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4.4 / 5.0
  13 customer reviews
Posted by anonymous | December 23, 2018
This review is from a person who hired this attorney.
| Hired Attorney
Best in the business
Helped two separate times and they were both very quick and you could tell he knew his stuff. Highly recommend Mr Hammer and will be the first person I think of in the future for anyone that needs his service
Posted by Ken | October 10, 2018
This review is from a person who hired this attorney.
| Hired Attorney
When circumstances become impossible to address
I would like to state first, that I believe life is basically good.However,there are times when hope and desperation become the only back-up plans to avail of themselves in difficult situations when circumstances become impossible to manage and our own understanding fails us. Two years ago my family was in turmoil, our relationship to one another almost severed, finances were dwindling...the horror of a teenage opiod abuser had befallen our youngest. An incomparable loss was settling into our lives as a young, bright and sensitive child slid into the darkness that is reserved for a heroin addict and their family. After a year of treatment things were only getting worse ( if that were possible )and felony charges for possession and theft began to accumulate, bringing with them an inexplicable helplessness which I had not experienced before or since. The stress was taking an enormous toll on my wife and myself...I cannot imagine what the agony my son was experiencing. After searching online for days, I could not separate one law firm from another, they all professed to be the one to call amid glowing ratings...I had to choose. Enter Mark Hammer and his associates. He is a gentleman, exudes confidence and relieves stress with his truth...and this was all within the first five minutes of our initial consult. After a thorough review, Mark began to address every legal issue confronting our son, he had already done his homework, which began to bring sanity back into our family as we sat there. At that time our son was facing years in prison, he is now recovering, on probation and living in a residence...drug free for five months. My family is healing, my son is healing. It was not easy but there was direction then and now. These were times which defined who I am today, my wife prays (that) Mark continues to help those who find themselves in circumstances like ours every night ; I admit, I sometimes chime in.
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Posted by anonymous | June 12, 2018
This review is from a person who hired this attorney.
| Hired Attorney
Best Criminal Attorney in St. Louis!!!
Not only is Mark knowledgable and have a good rapport with the judges and prosecutors, but he is kind and compassionate. Never once did I feel judged by Mark.
Posted by anonymous | June 5, 2018
This review is from a person who hired this attorney.
| Hired Attorney
THANK GOD FOR MARK HAMMER! I cannot begin to explain in words how thankful I am that I contacted the Hammer Law Firm when I found myself facing criminal legal charges. These are the important things about my experience that I will pass on: 1) I was treated with complete respect and never once felt any judgement from Mr. Hammer or his staff. I felt like he cared for me and my wife far beyond his fiduciary duty as my legal council. 2) I believe that Mr. Hammer's previous experience as a prosecuting attorney was instrumental in using strategies to ultimately arrive at a very desirable outcome. 3) The cost of my 3 year case was, in my opinion, extremely reasonable. 4) MOST IMPORTANT - There came times over this 3 year process where I had actually given up... especially towards the end. I had resigned to a accepting a plea that I was completely unhappy with simply out of fear of what the alternative could be. Even though I had given up, Mark did not. He kept fighting until, right before setting a trial date, the DA accepted the best case plea that we were hoping for from the very beginning. I shudder to think of what mine and my family's life could be like right now if I had called a different number 3 years ago, and me and my family will always be grateful beyond words for the role that Mark Hammer and The Hammer Law Firm played in our lives.
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Posted by John | April 1, 2018
This review is from a person who hired this attorney.
| Hired Attorney
Educated lawyer who will fight to win !!!
Mark and his entire staff worked dillegently to ensure I was kept up to speed on all Important details and dates of my legal situation. I felt Mark was truly vested in the successful outcome of my situation. He was able to successfully answer all legal, policy, and procedure questions , proving his education and comfort in his profession and with the legal system ! Highly recommend Mark and his entire staff if ever in need ! Criminal Defense Expert !
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Posted by anonymous | June 8, 2017
This review is from a person who hired this attorney.
| Hired Attorney
Amazing lawyer! Highly reommend him.
I am so blessed and thankful to have met such an excellent lawyer! He was honest, straight forward and always managed to get all my questions answered. Mark did anything and everything he could to defend me in my case. He kept me out of prison and from obtaining a criminal record. When I called him the first time he answered right away and made me feel that everything was going to be okay, and I was not wrong! I absolutely recommend him, he will get the job done and answer your questions and/or concerns. Do not hesitate on calling him if you need a lawyer!!!
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Posted by anonymous | January 17, 2017
This review is from a person who hired this attorney.
| Hired Attorney
Excellent Lawyer
This lawyer was able to keep me from obtaining a criminal record. Throughout the entire process him and his secretary were there to answer any questions that me and my family had.
Posted by Corey | April 28, 2015
I hired an attorney to help me with my case. Never being in trouble before, I didn't know exactly what to look for. The attorney I hired let my bond be revoked because he didn't inform the courts that I moved (even tho I gave him a month's notice in advance). While I was in jail, my fiancee found Mark Hammer, talked with him, and hired Mark on my behalf. Within a week or so, he had my bond reinstated, and a charge dropped. He kept me well informed on everything that was going on, and made me feel like I wasn't alone. When it was time for trial, Mark fought tooth and nail for me, and made the prosecuting attorney look like an amateur. After closing arguments, it only took the jury a little over an hour to return a not guilty verdict. Mark made me feel comfortable being in that setting. His knowledge and determination on winning is well worth his fees. I would recommend Mark to anyone that is going thru a similar situation!!
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Posted by Chandler | September 23, 2013
Couldn't go wrong with the Hammer (:
Mark is an amazing lawyer! He is straight forward with you about everything vary down to earth, not cocky whatsoever. He is the best thing so far that could have happen for my husband. He is willing to go the extra mile at all cost and we love him for that. We now unfortunately are using him as both state and federal legal representation but I don't think that honestly I would want anyone else for my husbands counsel.
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Posted by anonymous | December 23, 2012
Juvenile Law
I came to the internet in search of a lawyer experienced in juvenile law and without a clue I took a chance with the Hammer law firm. Sent Mark an e mail on a Sunday afternoon and within a few hours he called me and a few days later he drove three hours to our house and sat at our kitchen table and within a month or so the issue was resolved with a positive outcome. Would definitely recommend the Hammer law firm for a juvenile law case.
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Posted by anonymous | January 22, 2014
I was referred to Mr. Hammer by a former associate and this attorney did not let me down.. He lived up to the information my former associate gave me regarding him.. He told me he had many years of experience as a prosecutor and that was extremely valuable in helping me get the results I needed in this very trying time of my life.. He is very direct and straight forward and is very honest about what he can do for his clients .I appreciated his honesty..I would refer him to anyone that ends up in the same situation I found myself in....
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Posted by Cathy | December 5, 2021
This review is from a person who hired this attorney.
| Hired Attorney
Felt very abandoned
Our initial meeting with Mark went very well. He received a $1500 retainer from us that was not at all easy for us to come up with. The meeting lasted 3 hours and we left feeling confident that his assurances for a good outcome were well-grounded. If you consider only 2 other 30-second communications a good outcome, then he's your man! Needless to say, we didn't! We made 10-15 attempts to contact him via many possible options (his "personal" phone, texts, his office phone, e-mail, etc) with only the two successes. Even though we were instructed to put LOTS of information in Dropbox, which we did and which, consequently, took MANY hours, I don't know if he ever even looked at it because we haven't heard from him in a couple of months. His website is full of glorious testimonials. I would bet that MINE will never see the light of day!
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Posted by Susan | December 1, 2022
This review is from a person who hired this attorney.
| Hired Attorney
Did not get the results all these people are claiming so you may possibly do your own homework and find a lawyer through a live, reputable friend and not ask them how many clients they represented, but how many they saved from jail time. We found this guy on-line. We totally agree with Cathy at the very bottom of the reviews. He doesn't return calls or emails for long stretches while you're sitting there with anxiety. He doesn't even have an automatic, "I'll get back to you when possible" response or have an assistant contact you to relay he's tied up. Really felt like he didn't care about us but if you want to take a chance with your family's welfare, be my guest. We are on a 2nd lawyer hoping to fix the disappointing results we received. I blame us for trusting this attorney; especially when he wasn't returning calls. That should've been a huge RED FLAG to find different legal counsel.
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Contact for Details


AVVO RATING 8.1 (Excellent)

Work Experience

  • Adjunct Professor of Law
  • Saint Louis University
  • 2010 - Present
  • Managing Attorney
  • The Hammer Law Firm, LLC
  • 2009 - Present
  • Assistant Prosecuting Attorney
  • Ramsey County Attorney's Office
  • 2005 - 2009


  • University of Iowa College of Law
  • JD - Juris Doctor
  • 1986
  • University of Iowa
  • BS - Bachelor of Science
  • 1984


  • American Bar Association
  • Member
  • N/A
  • National Association of Criminal Defense Attorneys
  • Member
  • N/A
  • Missouri Association of Criminal Defense Attorneys
  • Member
  • N/A
  • Bar Association of Metropolitan Saint Louis
  • Member
  • N/A
  • Theodore McMillian American Inn of Court
  • Master of the Bench
  • N/A
  • Eastern District of the Missouri’s Criminal Justice Act (CJA) Program
  • Lead Panel Attorney
  • N/A
View all associations

Languages Spoken

  • English

Attorney endorsements

Received (5)
Given (2)
Endorse Mark
Criminal defense Attorney | Nov 22
Relationship: Co-worker
"I endorse this lawyer."
Criminal defense Attorney | Aug 11
Relationship: Opposing Counsel on matter
"When I was a prosecuting attorney I had the privilege of meeting Mark Hammer on a case. He was an aggressive and zealous advocate for his client and got his client a very favorable result. I was impressed by his skill and professionalism."
Criminal defense Attorney | Mar 27
Relationship: Fellow lawyer in community
"Mark is a wonderful attorney, and he taught me quite a bit about the practice of law. He has remarkable trial skills."
Criminal defense Attorney | Oct 28
Relationship: Fellow lawyer in community
"Mark is a skilled, smart attorney who works tirelessly to aid his clients."
Criminal defense Attorney | Sep 17
Relationship: Worked for lawyer
"A quick review of Mark's credentials will leave you with no doubt of his skill and experience. He was great to work for and he would be the first person I'd call if I ever needed assistance on a criminal matter."
Criminal defense
Criminal defense

Avvo Contributions

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Saint Louis Criminal defense Lawyer Mark Allan Hammer
Mark Allan Hammer
Criminal defense Attorney
Saint Louis, MO
Licensed for 36 years