| Hugh Bonneville | Robert Crawley, Earl of Grantham |
| Laura Carmichael | Lady Edith Crawley |
| Jim Carter | Charles Carson |
| Raquel Cassidy | Baxter |
| Brendan Coyle | John Bates |
| Michelle Dockery | Lady Mary Crawley |
| Kevin Doyle | Joseph Molesley |
| Joanne Froggatt | Anna Bates |
| Lily James | Lady Rose MacClare |
| Robert James-Collier | Thomas Barrow |
| Allen Leech | Tom Branson |
| Phyllis Logan | Mrs. Hughes |
| Elizabeth McGovern | Cora Crawley, Countess of Grantham |
| Sophie McShera | Daisy Mason |
| Lesley Nicol | Mrs. Patmore |
| Julian Ovenden | Charles Blake |
| David Robb | Dr. Clarkson |
| Maggie Smith | Violet Crawley, Dowager Countess of Grantham |
| Penelope Wilton | Isobel Crawley |
| Samantha Bond | Lady Rosamund Painswick |
| Emma Lowndes | Mrs. Drewe |
| Andrew Scarborough | Tim Drewe |
| Daisy Lewis | Sarah Bunting |
| Louis Hilyer | Inspector Vyner |
| Howard Ward | Sergeant Willis |
| Jeremy Swift | Spratt |
| Matt Barber | Atticus Aldridge |
| Douglas Reith | Lord Merton |
| Alex McNally | Cab Driver |
| Richard E. Grant | Simon Bricker |
| Rade Serbedzija | Prince Kuragin
(as Rade Sherbedgia) |
| Christopher Rozycki | Count Rostov |
| Catherine Steadman | Mabel Lane Fox |
| Oliver Barker | George Crawley
(uncredited) |
| Zac Barker | George Crawley
(uncredited) |
| Lauren Beacham | Bella Davis
(uncredited) |
| Georgina Bennett | Volunteer
(uncredited) |
| Julie Eagleton | Mother
(uncredited) |
| Eva Samms | Marigold Gregson
(uncredited) |
| Karina Samms | Marigold Gregson
(uncredited) |