Brendan formed his own law practice DONELON, P.C. at a young age. His firm now has offices in Kansas City and St. Louis. In the first half of his career, Brendan represented individuals in employment discrimination and wrongful termination cases. His practice now focuses on representing employees in class-action wage and overtime cases.

Brendan has tried numerous jury trials in state and federal courts and has extensive practice in briefing and arguing matters before most federal courts of appeals and the U.S. Supreme Court.

He has a strong interest in advocating for the civil liberties of all citizens and believes in the ACLU's role protecting constitutional rights.