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Tell Us About Your Case

"Lawyer of the Year"

Harris County Criminal Lawyers Association (2014)

Our Firm

Mercer and Keirnan

Mercer & Keirnan is a criminal defense law firm based in Houston, TX. Defense attorneys Michael D. Mercer and John "Casey" Keirnan co-founded "Mercer & Keirnan" in 2012 to provide high quality, experienced legal representation for anyone accused of a crime. The family tandem of John Keirnan and Michael Mercer have over 40 years of combined experience and are renowned by fellow criminal defense lawyers and by former Mercer & Keirnan clients as one of the best criminal defense firms in the state.

Houston Criminal Defense Lawyer

John P. "Casey" Keirnan

 Houston Criminal Defense Lawyer

Mercer & Keirnan

917 Franklin St #550

Houston, TX 77002

P: (713) 236-9700

F: (713) 236-1802

email: Jkeirnan@hotmail.com

John P. Keirnan, aka "Casey" Keirnan, has practiced criminal defense in Houston for over 40 years. His cases frequently appear in local and national news media. Mr. Keirnan is renowned both in Texas and around the country as a top criminal defense attorney who truly cares for the people he represents. In 2014, the Harris County Criminal Lawyers Association awarded Casey the coveted "Lawyer of the Year" award for his outstanding work in the field of criminal defense. 

Houston Criminal Defense Lawyer Michael Mercer

Mercer & Keirnan

917 Franklin St #550

Houston, TX 77002

P: (713) 236-9700

F: (713) 236-1802

email: mikedmercer@gmail.com

Michael D. Mercer

 Houston Criminal Defense Lawyer

Houston criminal defense lawyer 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. Former clients often rave about the incredible results Michael achieves for them in their time of need. He has handled over 1000 misdemeanor and felony cases in and around Harris County, the vast majority of which get dismissed or result in a not guilty verdict. Michael lives in Houston with his wife and three children. In addition to being a talented musician, Michael is a member of an award winning BBQ team here in Houston that regularly competes at the Houston Livestock Show and Rodeo as well as other local county fairs.

Client Reviews

MERCER & KEIRNAN

Average Rating: 5 out of 5 (11 reviews)

five-star-review-mercer-keirnan

"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

five-star-review-mercer-keirnan

"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

five-star-review-mercer-keirnan

"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

five-star-review-mercer-keirnan

"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

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