Brad Gillespie was raised in Macoupin County and graduated from Southwestern High School. Before obtaining his Bachelor of Liberal Studies at Southern Illinois University Edwardsville in 1999, Brad worked as a Union Laborer and Hod Carrier. He graduated from St. Louis University School of Law in 2003. Brad concentrated his legal studies in employment law, obtaining a Certificate in Employment Law from the William C. Wefel Center for Employment Law. He also served as a staff member and an editor on the Saint Louis University Law Journal.

For approximately ten years following law school, Brad represented injured workers in workers' compensation claims before the Illinois Workers' Compensation Commission. He worked for the State of Illinois in the Office of the Attorney General as an Assistant Attorney General in the General Law Bureau. In that role, he defended State employees in prisoner civil rights lawsuits. Finally, as Assistant Attorney General in the Environmental Bureau, he enforced environmental laws to protect the environment for future generations of Illinois residents. Brad is passionate about advocating for sick and injured people.