[2] In 1989, Cardwell opened a private practice that focused on criminal defense and civil litigation and also began working as an adjunct professor at the University of Richmond.
[2] In 1994, Cardwell became Chief Deputy Commonwealth's Attorney in Richmond, Virginia.
[2] In February 2013, Cardwell received the Carrico Professionalism Award from the Virginia State Bar Criminal Law Section.
[3][4] In November 2020, Cardwell was brought in as a special judge in Portsmouth, Virginia, to oversee a case in which the police department had filed charges against Virginia state senator Louise Lucas, Portsmouth Chief Public Defender Brenda Spry, and others who had been charged with felony destruction of a Confederate monument at a June 2020 protest.
[5] On August 16, 2021, Cardwell was elected to the Virginia Circuit Court in Richmond for an eight-year term which started on October 1, 2021.