| Hugh Bonneville | Robert Crawley, Earl of Grantham |
| Jessica Brown Findlay | Lady Sybil Branson
(credit only) |
| 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
(credit only) |
| 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 |
| Dan Stevens | Matthew Crawley |
| Penelope Wilton | Isobel Crawley |
| Shirley MacLaine | Martha Levinson |
| Robert Bathurst | Sir Anthony Strallan |
| Neil Bell | Durrant |
| Sarah Crowden | Lady Manville |
| Jason Furnival | Craig |
| David Robb | Dr. Clarkson |
| Lucille Sharp | Reed |
| Julie Eagleton | Wedding Guest
(uncredited) |