Robert Arnold worked on a local newspaper in Stamford before joining the Royal Academy of Dramatic Art in the early 1950s. He then went on to join the Royal Shakespeare Company in Stratford-upon-Avon where he met his wife, the actress June Brown. They appeared in several productions together. He appeared in two films, Sink The Bismark and Tunes of Glory, and several television productions, most notably Dixon of Dock Green which he was in for 7 years in the late 60s, early 70s. the family moved to Folkestone in 1970 where he appeared in local rep before moving back to London in the late 70s and joining The National Theatre.