In film, Jennings appeared in A Midsummer Night's Dream (as Theseus and Oberon), The Wings of the Dove (as Lord Mark, with Michael Gambon and Helena Bonham Carter), The Queen (as Prince Charles), The Four Feathers, Babel, and Bridget Jones: The Edge of Reason. Television work includes Hard Times, the PBS miniseries Liberty! (as King George III), and episodes of Inspector Morse, Waking the Dead, and Poirot.