As the Chief Deputy Solicitor General of Wisconsin, Walsh has briefed, managed, and argued dozens of appeals, prevailing on the merits in all cases to have reached final judgment.  He has received state and national awards for excellence in brief writing.  In 2016, Walsh was named to Forbes Magazine’s list of “30 Under 30” in the category of law and policy.

Before joining Wisconsin's Office of Solicitor General, Walsh practiced at Jones Day in Washington, D.C.  Previously, Walsh served as law clerk to Justice Antonin Scalia of the Supreme Court of the United States and Judge Diarmuid F. O’Scannlain of the United States Court of Appeals for the Ninth Circuit.  
Walsh, a Wisconsin native, graduated with High Honors from the University of Chicago Law School, where he was elected to the Order of the Coif, was named a Kirkland & Ellis Scholar, and served as Editor-in-Chief of the University of Chicago Law Review.  He holds a B.A., summa cum laude, from Hillsdale College.