Greg Brady is one of the main characters in the classic television show 'The Brady Bunch'. He is the oldest son of Mike and Carol Brady and is portrayed by Barry Williams. Cindy Brady is the youngest daughter of Mike and Carol Brady and is portrayed by Susan Olsen. Marcia Brady is the oldest daughter of Mike and Carol Brady and is portrayed by Maureen McCormick. All three characters are considered to be part of the iconic Brady family and are collectively referred to as 'One of the Bradys'.