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"Lawyer of the Year"

Harris County Criminal Lawyers Association (2014)

Michael D. Mercer

Top Houston Criminal Defense Lawyer

Mercer & Keirnan
917 Franklin St #550
Houston, TX 77002
P: (713) 236-9700
F: (713) 236-1802

Top Houston criminal defense attorney Michael D. Mercer worked for the Harris County District Attorney's office for one year before founding the criminal defense law firm of Mercer & Keirnan in 2012. Unlike other attorneys who practice multiple areas of law, Mr. Mercer devotes 100% of his practice to criminal defense, taking on clients charged with all misdemeanor and felony offenses.

Houston Criminal Defense Lawyer Michael Mercer

Since 2012, Michael has handled more than 1500 criminal cases in and around Harris County. More than 400 of those cases involved assault charges, aggravated assault charges and domestic violence charges. The vast majority of those cases resulted in either dismissal (without probation) or not guilty verdicts.

Client Reviews

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Michael Mercer Google Reviews

All of Mr. Mercer's clients are given his personal cell phone to encourage open communication. He has received over 100 5 star reviews online from the people he has helped.


Michael commands an impressive knowledge of the law and is an exceptional negotiator in the courtroom, as indicated by numerous former clients in online reviews and testimonials of Mercer & Keirnan. When Michael signs on to a case, he devotes himself fully to making sure his client gets the best possible result. Whether issuing subpoenas for hidden evidence, taking to the street to find and interview witnesses, or undergoing hours of research on the law, Attorney Michael Mercer goes above and beyond the duty he owes to his clients. His tireless work ethic and professionalism are propelling him to become one of the brightest and hard-nosed criminal defense lawyers at the courthouse.

MEMBER: Harris County Criminal Lawyers Association, Texas Criminal Defense Lawyers Association, Houston Young Lawyers Association


Average Rating: 5 out of 5 (11 reviews)


"Michael Mercer is a personal, professional, empathetic, diligent, caring and hard working who has the optimum interests of his clients at heart. He recently represented me in an assault family member case against me. Constantly assured me when I was down there was no evidence against me. He worked hard to have all cases dismissed in a lightning speed of time."

by A. O. January 29, 2024


"Michael Mercer and Casey Keirnan are some of the best criminal defense attorneys in Houston. I was facing an aggravated assault with a deadly weapon charge in Harris County and they got this felony assault case dismissed outright with no probation. Anyone charged with assault or aggravated assault in Houston should strongly consider calling Mercer and Keirnan Criminal Defense Attorneys. I couldn’t be happier with how they handled my case!"

by H. I. March 8, 2024


"I hired Mercer and Keirnan because of their experience handling DWIs and other charges.  Working closely with them throughout my case, it became very clear that I had made the right decision..."

by T. M. December 30, 2018


"Never been in trouble before and now I couldn't bond out of jail and had a court appointed lawyer who gave me little hope. I found defense attorney Casey Keirnan and Michael Mercer because of their experience as a theft defense lawyer. They replaced my court appointed attorney and everything changed."

by D. O. August 27, 2018


"I hired a top Houston drug lawyer with Mercer and Keirnan to defend my possession of a Controlled Substance Case. After a free consultation with Criminal defense attorney Michael Mercer, Mercer and Keirnan signed on to my case and after a few months my felony drug charge was dismissed!"
by RG One February 5, 2019

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