| Year | Title | Role | Notes |
| 1992 | The Camomile Lawn | Oliver | |
| 1996 | The Tenant of Wildfell Hall | Gilbert Markham | |
| 2000 | The Great Gatsby | Jay Gatsby | |
| 2001 | Perfect Strangers | Charles | |
| 2002 | Napoléon | Tsar Alexander I | |
| 2003 | Essential Byron | Reader | |
| 2003 | Cambridge Spies | Kim Philby | |
| 2003 | Agatha Christie's Poirot | Philip Blake | Episode: "Five Little Pigs" |
| 2004 | London | Casanova | |
| 2005 | Waking the Dead | Dr Nick Henderson | Episodes: "Subterraneans Part I" and "Subterraneans II" |
| 2005 | The Queen's Sister | Antony Armstrong-Jones | |
| 2006 | The Best Man | Peter Tremaine | |
| 2006 | Secrets of the Dead: The Umbrella Assassin | Narrator (voice) | Episode: "An account of the murder of Georgi Markov" |
| 2006 | Sharpe's Challenge | William Dodd | |
| 2006 | Jane Eyre | Edward Fairfax Rochester | |
| 2007 | The Wild West – Custer's Last Stand | General George Armstrong Custer | |
| 2008 | Wired | Crawford Hill | |
| 2009 | The Best Job in the World | Narrator (voice) | |
| 2009 | Robin Hood | Prince John of England | 3 episodes |
| 2010 | Strike Back | Arlington | |
| 2010 | Lost: The Mystery of Flight 447 | Narrator (voice) | |
| 2010 | Agatha Christie's Marple The Blue Geranium | George Pritchard | |
| 2010–2012 | Vexed | Jack Armstrong | |
| 2012 | Law & Order: UK | Prof. Martin Middlebrook | Episode: "Trial" |
| 2012 | Lewis | David Connelly | Episode: "Generation of Vipers" |
| 2014–2017 | Black Sails | James McGraw / Flint | 38 episodes |
| 2015 | And Then There Were None | Dr. Edward Armstrong | |
| 2018–2021 | Lost in Space | John Robinson | 28 episodes |
| 2019 | Summer of Rockets | Samuel Petrukhin | |
| 2021 | Alex Rider | Damian Cray | 6 episodes |
| 2022 | Prisoner C33 | Oscar Wilde | |
| 2023 | Six Four | Piers Fields-Turner | 2 episodes |
| 2023 | Dodger | President Van Buren | Episode: "Coronation" |
| 2024 | Percy Jackson and the Olympians | Poseidon | 2 episodes |
| 2024 | McDonald & Dodds | Mark Holgate | Episode: "The Rule of Three" |
| 2024 | One Day | Lionel | Episode 1.9 |
| 2024 | Batman: Caped Crusader | Gentleman Ghost / James "Jim" Craddock (voice) | |
| 2024 | The Split | Archie Moore | Two-part special |
| 2025 | A Cruel Love: The Ruth Ellis Story | Melford Stevenson | |
