Distinguished-looking, silvery-haired thespian, born Mark Richard Durden-Smith, son of A.J. Durden-Smith, fellow at the Royal College of Surgeons. His older brother was the documentary film maker Jo Durden-Smith. Richard attended Haileybury and Imperial Service College near Hertford and studied at Merton College in 1963. While at Oxford, he joined the Experimental Theatre Club, a student drama society which included among its alumni Michael Palin, Terry Jones and Dudley Moore. A classically-trained actor, Richard appeared on the London stage from 1968. As a member of the ensemble of the Royal Shakespeare Company, his many roles have included Claudio in Much Ado About Nothing, The Duke of Albany in King Lear, Count Paris in Romeo and Juliet, Theseus in A Midsummer Night's Dream, Polonius in Hamlet and Malvolio in Twelfth Night.

On the screen, Durden's gravitas and gentlemanly bearing have made him a shoo-in for casting as sophisticated, erudite intellectuals and well-bred aristocrats, senior government officials, barristers and military officers. While his main stock-in-trade has been in the genre of crime and mystery (Department S (1969), Special Branch (1969), Maigret (1988), Wycliffe (1993), The Bill (1984), Foyle's War (2002), Poirot (1989) and Endeavour (2012), to name but a few), Durden has latterly also graced many a period drama, notably episodes of Helen of Troy (2003) (as the Spartan king Tynadareus), The Borgias (2011) (a physician), Wolf Hall (2015) (Fisher, Bishop of Rochester), Jonathan Strange & Mr Norrell (2015) (Lord Liverpool, the Prime Minister) and Poldark (2015) (Dr. Anselm). A rare foray into science fiction saw him as an officer of the nefarious First Order in Star Wars: Episode IX - The Rise of Skywalker (2019). To date, his most recent appearance has been in the BBC One sitcom Ghosts (2019), as Charles Worthing, solicitor and legal counsel to the owners of (haunted) Button House.

Since 2017, Durden has been married to theatrical agent Rebecca Blond.