He gained prominence for his roles in Persuasion (1995), Hamlet (1996), My Week with Marilyn (2011), The Deep Blue Sea (2011), Mary Queen of Scots (2018), Benediction (2021), and The Outfit (2022).

In 2017, he portrayed Lavrentiy Beria in Armando Iannucci's The Death of Stalin, for which he received the British Independent Film Award for Best Supporting Actor.

[citation needed] Beale first came to the attention of theatre-goers in the late 1980s with a series of lauded comic performances, which were on occasion extremely camp, in such plays as The Man of Mode by George Etherege and Restoration by Edward Bond at the Royal Shakespeare Company (RSC).

He broadened his range in the early 1990s with moving performances as Konstantin in Chekhov's The Seagull, as Oswald in Ibsen's Ghosts, Ferdinand in The Duchess of Malfi and as Edgar in King Lear.

[5] It was at the RSC that he first worked with Sam Mendes, who directed him as Thersites in Troilus and Cressida, as Richard III and as Ariel in The Tempest, in the last of which he revealed a fine tenor voice.

[citation needed] Since 1995, he has been a regular at the National Theatre, where his roles have included Mosca in Ben Jonson's Volpone opposite Michael Gambon, George in Tom Stoppard's Jumpers and the lead in Humble Boy by Charlotte Jones, a part written specially for him.

The following year, he was a key part of Trevor Nunn's ensemble, playing in Leonard Bernstein's Candide (Voltaire/Pangloss), his "delivery of the lines [...] true to Voltaire in that it is simultaneously hilarious and horrible",[6] Edward Bulwer-Lytton's Money and Maxim Gorky's Summerfolk at the National.

[citation needed] In 2000, he played Hamlet in a production directed by John Caird for the National Theatre, a role for which he was described by The Daily Telegraph as "portly [and] relatively long in the tooth".

[citation needed] In 2008, he made his debut as a television presenter, fronting the BBC series Sacred Music with Harry Christophers and The Sixteen.

[12] He starred in a revival of Peter Nichols' Privates on Parade as part of Michael Grandage's new West End season at the Noël Coward Theatre from December 2012 to March 2013.

Beale appeared alongside John Simm in Harold Pinter's The Hothouse at the Trafalgar Studios from May to August 2013, directed by Jamie Lloyd.

In 2014, Beale was appointed the Cameron Mackintosh Professor of Contemporary Theatre at Oxford University, based at St Catherine's College.

In July 2018, Beale returned to the National, starring opposite Ben Miles and Adam Godley in The Lehman Trilogy, again directed by Mendes.

[23] During this time he re-rehearsed for the post-COVID return in late September of the Broadway transfer of the National Theatre production of The Lehman Trilogy whose run had been halted on 12 March 2020 by the pandemic.

Beale reprised his role (along with Adam Godley) but, due to stage commitments in London for the RSC in the third part of the Wolf Hall trilogy, Ben Miles was replaced by Adrian Lester.