Brandon C. Mayberry grew up in Jonesboro, Illinois. After high school, Brandon attended Shawnee Community College where he earned an Associates of Arts degree. He then attended Southern Illinois University, where he earned a B.A. in Paralegal Studies with a specialization in Pre-Law graduating Cum Laude. From there, Brandon went on to attend Southern Illinois University School of Law. Brandon graduated from the SIU School of Law. While in law school, Brandon was a member and marshal of the Phi Alpha Delta law fraternity. While attending SIU School of Law Brandon began working as a law clerk for the Law Offices of Armstrong and Green and continued to work there throughout law school. After graduating and being admitted to the Illinois Bar he became an Associate Attorney with the firm of Armstrong & Green.