Rupert Baker's life began in Folkestone, Kent, following his parents' return from a mission field in Nigeria, where his father worked as a doctor and his mother taught. He spent his early years in Deal and later in the Weald of Kent. At the age of 15, he relocated to Hythe, Kent, where his passion for acting flourished during frequent visits to the local cinema, The Ritz, where he would chain-smoke through endless double bills and collect old film posters donated by the manager, Don Blythe.
Due to his struggles with dyslexia, Rupert was unable to pursue a career in the RAF. However, he demonstrated exceptional talent in art and drama from a young age. Despite considering a career in graphic design and painting, Rupert ultimately decided to follow his passion for acting. He enrolled in the Webber Douglas Academy of Dramatic Art from 1979 to 1982, earning a Diploma with Merit. Additionally, he studied with renowned drama coach Jack Waltzer, a lifetime member of New York's Actor's Studio.
To make ends meet during the early years of his acting career, Rupert utilized his artistic skills to produce storyboards and graphic design work.