J.D. is a 2003 graduate of University of Mississippi, Summa Cum Laude, receiving a degree in Economics, and a 2006 graduate of the University of Mississippi School of Law. JD also studied international law at Downing College at Cambridge University, Cambridge, England.

After graduation, J.D. served as a Staff Attorney for Senior Circuit Court Judge Joseph H. Loper, Jr, of the Fifth Judicial Circuit Court District of Mississippi. He later served as Law Clerk to Chief United States Magistrate Judge John M. Roper of the United States District Court for the Southern District of Mississippi.

J.D. is a member of the Mississippi Bar and Harrison County Young Lawyers Association. He serves as a volunteer for the American Red Cross, Special Olympics, and the Mississippi Center for Prevention of Child Abuse. Johnson is an Eagle Scout and continues to serve as an Assistant Scoutmaster for the Boy Scouts of America.