Despite his success in film and television, Mark Williams remains deeply committed to theater. He has performed in numerous stage productions, earning critical acclaim for his interpretations of complex characters. His dedication to live performance highlights his passion for the craft and his respect for the theatrical tradition.
Some of his most notable theater roles include:
- "The History Boys" - National Theatre
- "The Seagull" - Royal Shakespeare Company
- "The Caretaker" - West End
