During this time he was involved with many new and influential plays, including Tom Stoppard's Rosencrantz and Guildenstern are Dead and Jumpers, Peter Shaffer's The Royal Hunt of the Sun and Adrian Mitchell's Tyger.

[1] Other work at the National Theatre included Guys and Dolls, The Beggar's Opera, Coriolanus (for which he won the Clarence Derwent Award in 1985) and Animal Farm, The School for Wives, Wild Oats, Democracy and The UN Inspector.

In 1979 Ryall played a small role as a mechanic in the episode, Earnshaw Strikes Back, in the long running BBC series Last of the Summer Wine.

In 1996–97, working with the Royal Shakespeare Company, he played God in The Mysteries, and Polonius in Hamlet, for which he was nominated for the Helen Hayes Award during its tour of the United States.

Ryall continued to be a regular face in the theatre: with appearances in Patrick Marber's Don Juan in Soho at the Donmar Warehouse in 2007.

Ryall's television and film career included The Knowledge, The Singing Detective, Shelley, Inspector Morse,Heartbeat, Doc Martin, Midsomer Murders, Bertie and Elizabeth, Juliet Bravo, Down to Earth, Foyle's War, Plotlands, State of Play, The Elephant Man, Truly, Madly, Deeply, Black Beauty and Two Men Went to War.