| Hugh Bonneville | Robert Crawley, Earl of Grantham |
| Laura Carmichael | Lady Edith Crawley |
| Jim Carter | Charles Carson |
| Brendan Coyle | John Bates |
| Michelle Dockery | Lady Mary Crawley |
| Kevin Doyle | Joseph Molesley |
| Siobhan Finneran | Sarah O'Brien |
| Joanne Froggatt | Anna Bates |
| Robert James-Collier | Thomas Barrow
(as Rob James-Collier) |
| Allen Leech | Tom Branson |
| Phyllis Logan | Mrs. Hughes |
| Elizabeth McGovern | Cora Crawley, Countess of Grantham |
| Sophie McShera | Daisy Mason |
| Matt Milne | Alfred Nugent |
| Lesley Nicol | Mrs. Patmore |
| Amy Nuttall | Ethel Parks |
| Maggie Smith | Violet Crawley, Dowager Countess of Grantham |
| Ed Speleers | Jimmy Kent |
| Dan Stevens | Matthew Crawley |
| Penelope Wilton | Isobel Crawley |
| Edward Baker-Duly | Terence Margadale |
| Samantha Bond | Lady Rosamund Painswick |
| Charles Edwards | Michael Gregson |
| Bernard Gallagher | Bill Molesley |
| Lily James | Lady Rose MacClare |
| Edmund Kente | Mead |
| Jordan Long | Taxi Driver |
| Christine Mackie | Daphne Bryant |
| David Robb | Dr. Clarkson |
| Richard Teverson | Dr. Ryder |
| Cara Theobold | Ivy Stuart |
| Tony Turner | Inspector Stanford |
| Lily-Fleur Bradbury | Night-club Dancer
(uncredited) |