Mark trained at RADA under Hugh Cruttwell and at The Chrysalis Theatre School, Balham, with Barbara Bridgmont.
He is the Artistic Director of Shakespeare's Globe and Phoebus’ Cart Theatre Company. He is also an Associate Artist of the RSC and a friend of the Francis Bacon Research Trust.
The Citizen's Theatre (Glasgow) gave him his first job in 1980 and since then he has worked with the RSC, Royal National Theatre, Royal Opera House, Scottish Ballet, Shared Experience, Bush Theatre, Tricycle Theatre and London Theatre of the Imagination. Mark has also worked with Contact Theatre, Oxford Playhouse, Project Theatre (Dublin), Mermaid Theatre, Royal Court, American Repertory Theatre (Boston), Theatre for a New Audience (New York), Pittsburgh Playhouse and Thelma Holt, after whose production of Much Ado About Nothing he received the Olivier Award for Best Actor.
In the Globe's Prologue Season in 1996 he played Proteus in The Two Gentlemen of Verona in London and New York. In 1997 Mark directed Triumphs and Mirths for Her Majesty the Queen and played Henry V in the Globe's Opening Season. In 1998 he played Bassanio in The Merchant of Venice and Hippolito in Thomas Dekker's The Honest Whore. The 400th Anniversary 1999 Season saw Mark as Master of Play for Julius Caesar as well as playing Cleopatra in Antony and Cleopatra. For the 2000 season he played the titular role in Hamlet and appeared in The Antipodes, and in 2001 he played Posthumous/Cloten in Cymbeline.
Television: The Grass Arena, Loves Lies Bleeding, In Lambeth and Loving. Film: Prospero's Books by Peter Greenaway, The Institute Benjamenta by Brothers Quay, Angels and Insects, Hearts of Fire and Intimacy.