Allen Tanner has extensive experience in representing people who are facing serious criminal charges. During his years as a criminal defense lawyer, he has represented thousands of individuals charged with all types of felony offenses. He has tried felony jury trials involving capital murder, sexual assault, burglary, aggravated robbery, Medicare fraud and drugs. He has tried 15 death penalty cases to juries in Houston, Victoria, Fredericksburg, Corpus Christi and Austin. His most newsworthy case was that of Angel Maturino Resendez, known as the "Railroad Killer," in February of 2000.

Many of Allen Tanner's clients plead Not Guilty and take their case before a jury. As to the guilt issue, Allen Tanner realizes that nothing in life is more serious than to be falsely accused of committing a crime. He understands that serving time for a crime you did not commit is unimaginable. However, many clients choose to admit their guilt. Allen Tanner then attempts to lessen their punishment whereby they receive pretrial diversion, deferred adjudication or a lesser sentence from a jury. He often uses psychiatric testimony to attempt to explain and mitigate his clients’ actions.

Allen Tanner graduated from Johns Hopkins University in 1978 and the University of San Francisco School of Law in 1981. After passing the Texas Bar exam in 1981, he worked as a prosecutor at the Harris County District Attorney's office in Houston until 1985, when he opened his own private law practice. The only types of cases he has handled are criminal defense cases. Allen Tanner became Board Certified in criminal law by the Texas Board of Legal Specialization in 1989. He has never been disciplined by the state bar of Texas.