After Warwick University, Alex trained at the Bristol Old Vic Theatre School.
His theatre credits include – for the National Theatre: Garry Essendine in Present Laughter, Subtle in The Alchemist, George W. Bush in David Hare's Stuff Happens, Walter Burns in His Girl Friday, Leontes in The Winter's Tale and Lord Foppington in The Relapse, for which two roles he won the Evening Standard Drama Award for Best Actor in 2001, the title role in Albert Speer and Professor Higgins in My Fair Lady (Olivier Award for Best Actor in a Musical, 2003).
For the RSC his roles include Richard II, Peer Gynt (Olivier Award, Best Actor, 1996), Theseus and Oberon (also on US tour and on Broadway), Angelo, Benedick and Hamlet (also in the US, Helen Hayes Award, Best Actor, 1998). He is an Associate Actor of both the National Theatre and the RSC.
West End appearances include Too Clever By Half (Olivier Award, Best Comedy Performance and London Theatre Critics Award, Best Actor, 1988), The Wild Duck, The Importance of Being Earnest with Dame Maggie Smith, and as Voltaire and Dr. Pangloss in Candide with the English National Opera (2008).
His television appearances include Smiley's People, Inspector Morse, the title role in Ashenden, Hard Times, Bad Blood, as Alastair Campbell in A Very Social Secretary, as Serge Dianghilev in Riot at the Rite, Poirot: Cards on the Table, Waking the Dead, Spooks, The State Within, Cranford, Rapunzel, as John le Mesurier in Hancock and Joan, 10 Days to War and Whitechapel.
Films include A Midsummer Night's Dream, The Wings of the Dove, Joseph and His Amazing Technicolor Dreamcoat, Four Feathers, Five Children and It, Bridget Jones: The Edge of Reason, Babel, and as Prince Charles in Stephen Frears's film, The Queen.
He has worked extensively in radio, recently as George in Who's Afraid of Virginia Woolf?, Henry in Tom Stoppard's The Real Thing, Sir Robert Chiltern in An Ideal Husband as Nick Jenkins in A Dance to the Music of Time, as well as recording many audio books.