Marbury is a native of Selma, Alabama.  He graduated from the University of Alabama in 1970 and Harvard Law School in 1975.  In between college and law school he served as a lieutenant in the United States Army, Southern Command, stationed in Panama.

Following law school in 1975, he joined the Atlanta law firm of King and Spalding, which he left in 1981 to become a founding partner of his current firm Parker, Hudson, Rainer & Dobbs.  He is recognized by Chambers USA as a Leading Business Lawyer, is included in "The Best Lawyers in America" for Commercial Litigation, and has been selected for many years as a Georgia "Super Lawyer" by Law and Politics Magazine.

Marbury currently serves the Kiwanis Club as a member of the Board of Trustees of the Kiwanis Foundation of Atlanta and as co-chair of the Program Committee.  He just finished a four-year term as Chair of the University of Alabama President's Cabinet and has served his alma mater in many other roles over the years.  He is a past president of the Harvard Law School Association of Georgia.  Marbury currently is a board member of Atlanta Community Ministries and the Georgia Justice Project.  He has served as deacon chair in his prior church, taught adult Sunday School classes for many years, and currently co-teaches the Anchor Class at Peachtree Presbyterian Church.

Marbury and his wife Kathy live in Buckhead.  They have two grown sons who live nearby and two grandchildren.