He graduated from the Guildhall School of Music and Drama and spent several seasons working in repertory theatres in Sheffield, Manchester, Leicester and Oxford among others.

In 1975, he made his West End debut in The Gay Lord Quex, opposite Judi Dench, which was directed by Sir John Gielgud at the Albery Theatre.

While playing Dean Rebel in Trafford Tanzi at London's Mermaid Theatre, he was spotted by the producers of the NBC mini-series A.D., who cast him in the lead role of Valerius.

He also appeared alongside Barbara Windsor, Joss Ackland and Gareth Hunt in the Pet Shop Boys film, It Couldn't Happen Here, Lionheart, David Lynch's Inland Empire, King of the Wind, Ridley Scott's Body of Lies and Charles Dennis's The Favour of Your Company and Chicanery.

Dickson's game credits include Eternal Darkness, Age of Empires III, Heroes of Might and Magic V: Hammers of Fate, and The Elder Scrolls V: Skyrim.