A versatile actor and a founding member of the Royal Shakespeare Company in 1960, Richardson starred as Jean-Paul Marat in Marat/Sade on Broadway in 1965. He was nominated for a Tony Award for his portrayal of Henry Higgins in a Broadway revival of My Fair Lady in 1976. His best known role was Francis Urquhart in the BBC series House of Cards, To Play the King, and The Final Cut.
In America, he may have been best known from a commercial in which he asked "Pardon me, would you have any Grey Poupon?" from inside a Rolls-Royce.