Ann earned a BA degree from the University of Texas and her law degree from South Texas College of Law Houston. She worked as a briefing attorney for the Honorable Leslie Brock Yates, then a Justice on the Fourteenth Court of Appeals following graduation. She then worked as a prosecutor with the Harris County District Attorney's Office until 2005, when she then entered private practice with her father, Jake, at Johnson Law Firm PC. Ann and her father represented individuals in civil, criminal and juvenile matters. One of her most significant cases was In re B.W., 313 SW3rd 818 (Tex. 2010) in which the Texas Supreme Court reversed the Harris County District Attorney's prosecution of a 13-year-old child for prostitution and created a framework for protecting child victims of exploitation and human trafficking. Ann was a founding member of the Harris County GIRLS Court (now called CARE Court), a special court dedicated to assisting children lawfully brought to the juvenile justice system who may also be victims of human trafficking.

In 2013, Ann returned to the Harris County District Attorney's Office to be the Human Trafficking Specialist. Ann successfully prosecuted some of the worst traffickers and her work eventually led to the establishment of the Human Trafficking Section where she served as the Chief Prosecutor until 2017. In addition to holding exploiters accountable, Ann worked to modify Harris County's approach to better identify victims who were misidentified as offenders with a model of "arrest as recovery, not conviction." Ann also established S.A.F.E. Court after receiving a Department of Justice grant to provide support to those 17 to 25 - years of age arrested for prostitution.

Ann was a founding partner in private practice with Johnson Martinez LLC working on behalf of human trafficking victims and indigent defendants in our criminal justice system. Ann returned to her family firm, Johnson Law Firm PC in 2021, which was established by her father, Jake Johnson, in 1980.

Ann has been an adjunct professor of law at South Texas College of Law Houston since 2001. She teaches courses on voir dire and jury communication, trial litigation and criminal defense. She is also an active member of the Texas Children's Justice Act Task Force.

Ann is honored to have been elected to serve as State Representative for Texas House District 134 in 2020.

A Houston native and youngest of six children, Ann learned her values and work ethic at home. Ann's father, former State Representative Jake Johnson from Harris County (59th and 60th sessions. And her mother, Hon Carolyn Marks Johnson, has a strong sense of the honor and responsibility of speaking for those who cannot speak for themselves.

Ann and wife Sonya Cuellar, an artist, married as soon as the law allowed. They have three rescue dogs and lots of wonderful nieces and nephews.