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About me

Criminal Defense Attorney, William Byrnes, of Byrnes Law Firm LLC has earned a reputation in the legal community for being a tough and determined advocate since 1999. National Awards and Honors In 2013, he was inducted into the The National Advocacy for DUI Defense (NAFDD) – an invitation-only organization identifying the very best private DUI attorneys in the nation. Bill was specifically honored for being in the top 100 DUI attorneys out of 24,423 attorneys in Missouri. He aggressively challenges illegal search and seizures and numerous victories resulting in all of the State’s evidence being disregarded before trial by arguing violations of his client’s Constitutional Rights under the Fourth Amendment. Bill has been told by judges in St. Charles and St. Louis County, that he is one of the only attorneys that consistently works with his clients to resolve their drug addiction before their final court date. If Bill can help your family member or friend get clean, he will, and has a long record to prove it. You can also bet, Bill’s reputation for success weighs heavily in the courtroom. Attorney Bill Byrnes, received his Juris Doctor from Thomas Cooley Law School in 1999 where he was invited to study on academic scholarship and graduated Cum Laude, at the top 10% of his class. Bill has been in private practice since 2001 with the opening of Byrnes Law Firm LLC which is now located at 1000 Fairgrounds Road, Suite 103, St. Charles, MO 63301. Not only is Bill highly regarded as one of the best, he is also one of the most compassionate attorneys in the area, considered approachable and easy to talk to. He will fully listen to you until you have completely recounted your side of the story regarding all of the events leading up to your arrest. He will explain your rights, provide answers to all of your questions and help calm your anxiety. His firm, Byrnes Law Firm LLC, accepts payment plans, credit cards and bond assignments. The first office consultation is FREE. Other than living three years in Michigan while attending Law School, Bill has lived in the St. Louis and St. Charles areas his entire life. He feels the back bone of his success is his family. Bill has been married to his college sweetheart for 17 years and has three amazing sons he hopes to someday be in practice with. With Bill by your side, you will always receive experienced representation, as well as a long track record of success. Contact us to schedule your free consultation at 636-896-4300. Bill Byrnes, founder of the law firm, represents clients facing serious felonies in St. Louis, St. Charles, Franklin, Warrenton, Lincoln and Montgomery, Missouri. He is noted for excelling in drug, alcohol, and assault and burglary law across Missouri.


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Contact info

Byrnes Law Firm

1000 Fairgrounds Rd, Suite 103
St. Charles, MO, 63301

Practice areas


  1. DUI & DWI: 90%
    17 years, 3.93 thousand cases
  2. Criminal Defense: 10%
    17 years, 1.69 thousand cases



Fixed (sometimes), Retainer (always), Free consultation (60 minutes)

Payment types:

Cash, Check, Credit card

Attorney endorsements

18 total 

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  • Ross W. Buehler

    I endorse this lawyer.


    Ross Buehler Criminal defense Attorney
    Relationship: Fellow lawyer in community

  • Joanne P Underhill

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    Joanne Underhill Business Attorney
    Relationship: Opposing Counsel on matter


MOGood Standing, Active200001/08/2013
We have not found any instances of professional misconduct for this lawyer.
Avvo contributions
Legal answers
Award nameGrantorDate granted
Recognized AttorneyIs That Legal2015
Top 100 Dwi AttorneysNational Advocacy for DUI Defense2014
Top 100 AttorneyNational Advocacy for DUI Defense2013
Magna Cum LaudeWestern Michigan University Law School2000
Honors ScholarshipWestern Michigan University Law School1995
Work experience
TitleCompany nameDuration
Founding PartnerByrnes Law Firm LLC2001 - Present
Association namePosition nameDuration
Missouri Association of Criminal Defense LawyersAssociate Member2015 - Present
National Advocacy for DUI DefenseAdmitted2013 - Present
Missouri State BarN/A2000 - Present
Thomas M. Cooley American Inn of CourtAttorney Member1999 - Present
Legal cases
Case nameOutcome
Felony Possession and DistributionClient paid a fine and was released
See all legal cases 
Publication nameTitleDate
Byrnes WebsiteAbuse of Power By Police Officers2015
Chamber MagazineWhat To Do In The First Few Hours of an Arrest?2014
School nameMajorDegreeGraduated
Thomas M. Cooley Law SchoolLawJD - Juris Doctor1999
Southeast Missouri State UniversityCriminal JusticeBS - Bachelor of Science1995
Speaking engagements
Conference nameTitleDate
Morning Show Ask the ExpertF&Q with Bill Byrnes2014
Chamber of Commerce EventDWI Defense2014