- Sean Bean as Lord Eddard Stark, Lord of Winterfell.
- Michelle Fairley as Lady Catelyn Stark, originally of House Tully.
- Richard Madden as Robb Stark, Eddard's eldest son and heir.
- Sophie Turner as Sansa Stark, Eddard's eldest daughter.
- Maisie Williams as Arya Stark, Eddard's youngest daughter.
- Isaac Hempstead-Wright as Bran Stark, Eddard's middle son.
- Art Parkinson as Rickon Stark, Eddard's youngest son.
- Kit Harington as Jon Snow, Eddard's bastard son by an unknown mother.
- Joseph Mawle as Benjen Stark, Eddard's younger brother, First Ranger of the Night's Watch.
Retainers at Winterfell
- Alfie Allen as Theon Greyjoy, a ward and hostage for his rebellious father's good behavior.
- Ron Donachie as Ser Rodrik Cassel, master of arms.
- Jamie Sives as Jory Cassel, Rodrik's nephew, captain of the guards.
- Phil Dixon as Tomard, a guardsman.
- Graham Charles as Varly, a guardsman.
- Donald Sumpter as Maester Luwin, a maester of the Citadel.
- Kristian Nairn as Hodor, a simple stableboy.
- Margaret John as Old Nan, a retired servant and Hodor's great-grandmother.
- Susan Brown as Septa Mordane, a religious tutor and governess to Arya and Sansa.
- Esme Bianco as Ros, a prostitute working in Winterfell's outlying town.
Vassals and allies of House Stark
- Clive Mantle as Lord Greatjon Umber, Lord of Last Hearth, a loyal vassal of House Stark.
- Mark Coney as Lord Galbart Glover, Lord of Deepwood Motte, a vassal of House Stark.
- Steven Blount (Season 1)/John Stahl (Season 2) as Lord Rickard Karstark, Lord of Karhold, a vassal and distant kinsman of House Stark.
- Thomas Brodie-Sangster as Jojen Reed, the son and heir of Lord Howland Reed, one of Eddard Stark's closest friends and allies.
- Ellie Kendrick as Meera Reed, Jojen's older sister.
House Bolton and retainers
- Michael McElhatton as Lord Roose Bolton, Lord of the Dreadfort, a vassal of Eddard Stark.
- Iwan Rheon as Ramsay Snow, Lord Roose's bastard son.
- Noah Taylor as Locke, a vassal and hunter in Lord Bolton's service.
- Charlotte Hope as Myranda, a prostitute at the Dreadfort.
- Charles Dance as Lord Tywin Lannister, the widowed patriarch of House Lannister and father of Jaime, Cersei and Tyrion.
- Lena Headey as Queen Cersei Lannister, Queen of the Seven Kingdoms, twin sister of Jaime, mother of Joffrey, Myrcella and Tommen.
- Nikolaj Coster-Waldau as Ser Jaime Lannister, a knight of the Kingsguard, twin brother of Cersei.
- Peter Dinklage as Tyrion Lannister, Cersei and Jaime's younger brother, called the Imp for his size.
- Ian Gelder as Ser Kevan Lannister, Lord Tywin's younger brother and closest adviser.
- Eugene Simon as Lancel Lannister, Ser Kevan's son, a squire to King Robert.
- Karl Davies as Alton Lannister, a distant cousin of the main branch of the family.
Vassals and allies of House Lannister
- Daniel Portman as Podrick Payne, a squire, a member of one of the Lannisters' vassal families.
- Fintan McKeown as Ser Amory Lorch, a loyal vassal and retainer of House Lannister.
- Rory McCann as Sandor Clegane, Prince Joffrey's bodyguard and sworn sword, long in the service of House Lannister.
- Conan Stevens (Season 1)/Ian Whyte (Season 2)/Hafþór Júlíus Björnsson (Season 4) as Ser Gregor Clegane, Sandor Clegane's brother and the most feared knight in Westeros, known as 'Lord Tywin's Mad Dog'.
- Anthony Morris as the Tickler, a noted interrogator and torturer in the service of Ser Gregor Clegane.
- Vinnie McCabe as Lord Leo Lefford, a Lannister bannerman.
- Mark Addy as King Robert Baratheon, King of the Seven Kingdoms.
- Jack Gleeson as Prince Joffrey Baratheon, King Robert's eldest son and heir.
- Aimee Richardson as Myrcella Baratheon, King Robert's eldest daughter.
- Callum Wharry as Tommen Baratheon, King Robert's youngest son.
- Gethin Anthony as Lord Renly Baratheon, King Robert's youngest brother, Lord of Storm's End.
- Stephen Dillane as Lord Stannis Baratheon, King Robert's middle brother, Lord of Dragonstone.
- Tara Fitzgerald as Lady Selyse Baratheon, Lord Stannis's wife, originally of House Florent.
- Kerry Ingram as Shireen Baratheon, Lord Stannis's daughter and only child.
Vassals and allies of House Baratheon
- Carice van Houten as Melisandre, Lord Stannis's adviser, a red priestess.
- Liam Cunningham as Ser Davos Seaworth, a former smuggler, now Lord Stannis' most loyal vassal.
- Kerr Logan as Matthos Seaworth, Ser Davos's son.
- Oliver Ford Davies as Maester Cressen, Lord Stannis's maester.
- Lucian Msamati as Salladhor Saan, a freesail in Stannis's employ.
- Gordon Mahn as Ser Imry Florent, a knight sworn to Stannis's service.
- Gwendoline Christie as Brienne of Tarth, a fierce warrior from the Stormlands.
- Robert Sterne as the Royal Steward, a courtier in the service of Robert Baratheon in King's Landing.
- Rhodri Hosking as Mycah, son of a butcher in King Robert's retinue.
House Arryn and retainers
- Sir John Standing as Lord Jon Arryn, Lord of the Eyrie and the King's Hand.
- Kate Dickie as Lady Lysa Arryn, originally of House Tully, Catelyn Stark's sister.
- Lino Facioli as Robin Arryn, Lord Jon's only surviving son and heir.
- Brendan McCormack as Ser Vardis Egen, the captain of the Eyrie's household guards.
- Ciaran Birmingham as Mord, the Eyrie's chief gaoler.
- Jefferson Hall as Ser Hugh of the Vale, Lord Jon's former squire.
- Rupert Vansittart as Lord Yohn Royce, one of the Arryns' most stalwart vassals and supporters.
- Paola Dionisotti as Lady Anya Waynwood, one of the Arryns' vassals.
- Alisdair Simpson as Ser Donnel Waynwood, the Knight of the Gate.
House Tyrell and retainers
- Roger Ashton-Griffiths as Lord Mace Tyrell, Lord of Highgarden and the Reach. The son of Olenna Redwyne and the father of Loras and Margaery.
- Finn Jones as Ser Loras Tyrell, Lord Renly Baratheon's former squire and a famous tourney knight.
- Natalie Dormer as Margaery Tyrell, Loras's sister.
- Dame Diana Rigg as Olenna Redwyne, nicknamed the Queen of Thorns, the mother of Mace, grandmother of Loras and Margaery and matriarch of the family.
House Greyjoy and retainers
- Patrick Malahide as Lord Balon Greyjoy, Lord of Pyke, father of Theon Greyjoy.
- Gemma Whelan as Yara Greyjoy, the only daughter of Lord Balon.
- Forbes KB as Lorren, a noted raider and reaver in the service of House Greyjoy.
- Ralph Ineson as Dagmer, a noted raider, reaver and ship captain in the service of House Greyjoy.
House Tully and retainers
- Tobias Menzies as Ser Edmure Tully, the son and heir of the ailing Lord Hoster Tully and the brother of Lady Catelyn Stark.
- Clive Russell as Ser Brynden Tully, Lord Hoster's younger brother, a famous knight known as "The Blackfish".
- Gerry O'Brien as Lord Jonos Bracken, Lord of Stone Hedge, a vassal of House Tully.
- Kevin Keenan as Kurleket, a man-at-arms to House Bracken, a vassal of House Tully.
- Ryan McKenna as Ser Willis Wode, a sworn sword of House Whent, a vassal of House Tully.
House Frey and retainers
- David Bradley as Lord Walder Frey, Lord of the Twins, an old and prickly vassal of House Tully, past ninety years of age.
- Kelly Long as Joyeuse Erenford, Walder Frey's newest wife.
- Tim Plester as "Black Walder" Frey, the great-grandson of Walder Frey and a noted warrior with a hot temper.
- Alexandra Dowling as Roslin Frey, one of Lord Frey's youngest daughters.
- Elizabeth Webster as Fat Walda Frey, one of Lord Frey's granddaughters.
House Martell and retainers
- Pedro Pascal as Prince Oberyn Martell, popularly known as the Red Viper. The younger brother of the ruling Prince Doran Martell of Dorne.
- Indira Varma as Ellaria Sand, Oberyn's paramour and mother to several of his children.
- Daniel Rabin as Lord Blackmont, a senior vassal of the Martells.
In the Riverlands
- Susie Kelly as Masha Heddle, the innkeeper of the Crossroads Inn.
- Jerome Flynn as Bronn, a sellsword met at the Crossroads Inn.
- Emun Elliott as Marillion, a singer and troubadour met at the Crossroads Inn.
- Sibel Kekilli as Shae, a camp-follower and prostitute attached to the Lannister army.
- Mark Lewis Jones as Shagga, a warrior clan chief from the Mountains of the Moon.
- Oona Chaplin as Talisa Maegyr, a battlefield doctor.
- Paul Kealyn as Weasel, a worker at Harrenhal.
- Paul Kaye as Thoros of Myr, a red priest, warrior, famed drinker and friend of King Robert.
- Philip McGinley as Anguy, an exceptionally-skilled archer.
- Anton Lesser as Qyburn, a disgraced maester.
In King's Landing
- Aidan Gillen as Lord Petyr 'Littlefinger' Baelish, the Master of Coin on the king's small council.
- Julian Glover as Grand Maester Pycelle, the master of wisdom on the king's small council.
- Conleth Hill as Varys, the Master of Whisperers on the king's small council.
- Ian McElhinney as Lord Commander Barristan Selmy, the head of the Kingsguard.
- Ian Beattie as Ser Meryn Trant, a knight of the Kingsguard.
- James Doran as Ser Mandon Moore, a knight of the Kingsguard.
- Wilko Johnson as Ser Ilyn Payne, the king's headsman and executioner.
- David Michael Scott (Season 1)/Richard Dormer (Season 3) as Lord Beric Dondarrion, a young lord and popular tourney knight.
- Dominic Carter as Commander Janos Slynt, the commander of the City Watch.
- Miltos Yerolemou as Syrio Forel, a master swordsman from Braavos.
- Andrew Wilde as Tobho Mott, a master armorer and smith.
- Joe Dempsie as Gendry, Mott's apprentice.
- Antonia Christophers as Mhaegen, a prostitute.
- Sahara Knite as Armeca, a prostitute.
- Emily Diamond as a prostitute.
- Josephine Gillan as Marei, a prostitute.
- Will Tudor as Olyvar, a male prostitute and spy.
- Pixie Le Knot as Kayla, a prostitute and contortionist.
- Eros Vlahos as Lommy Greenhands, a dyer's apprentice.
- Ben Hawkey as Hot Pie, a baker's apprentice.
- Andy Beckwith as Rorge, a street criminal imprisoned in the Red Keep.
- Gerard Jordan as Biter, a street criminal imprisoned in the Red Keep.
- Hugo Culverhouse as a stableboy in the Red Keep.
- Tom Wlaschiha as Jaqen H'ghar, a prisoner in the Red Keep.
- Roy Dotrice as Wisdom Hallyne, the head of the Alchemists' Guild.
- Simon Fisher-Becker as the High Septon, the head of the Faith of the Seven.
- Tony Way as Ser Dontos Hollard, a knight in service to the crown.
- Mark Gatiss as Tycho Nestoris, a representative of the Iron Bank of Braavos to the Iron Throne.
In the Night's Watch
- James Cosmo as Lord Commander Jeor Mormont, commander of the Night's Watch.
- Owen Teale as Ser Alliser Thorne, in charge of training new recruits.
- Peter Vaughan as Maester Aemon, Lord Mormont's closest adviser.
- Brian Fortune as Bowen Marsh, the First Steward of the Watch.
- Dennis McKeever as Othell Yarwyck, the First Builder of the Watch.
- Jeffrey O'Brien as Ser Jaremy Rykker, an officer in the rangers.
- Francis Magee as Yoren, a recruiter for the Watch.
- John Bradley-West as Samwell Tarly, a nobleman's son, a fresh recruit to the Wall.
- Josef Altin as Pypar, a fresh recruit to the Watch, a former actor.
- Mark Stanley as Grenn, a fresh recruit to the Watch.
- Luke McEwan as Rast, a fresh recruit to the Watch, arrested for rape.
- Rob Ostlere as Ser Waymar Royce, a newcomer to the Watch, a skilled knight.
- Dermot Keaney as Gared, an experienced ranger.
- Bronson Webb as Will, an experienced ranger and scout.
- Ben Crompton as Eddison Tollett, a squire, noted for his pessimistic sense of humor.
- Simon Armstrong as Qhorin Halfhand, an elite scout from the Shadow Tower and one of the Watch's most respected rangers.
- Burn Gorman as Karl, a ranger.
- Natalia Tena as Osha, a wildling warrior-woman.
- Stephen Don as Stiv, a former member of the Watch who has turned his cloak.
- Robert Pugh as Craster, a wildling whose keep provides a safehaven for rangers of the Watch.
- Hannah Murray as Gilly, one of Craster's daughters.
- Rose Leslie as Ygritte, a wildling warrior-woman in the service of Mance Rayder.
- Edward Dogliani as Lord of Bones, a famed wildling warrior and leader of men, a fierce enemy of the Night's Watch.
- Mackenzie Crook as Orell, a sinister wildling with unnatural powers.
- Kristofer Hivju as Tormund Giantsbane, a charismatic wildling leader.
- Ciarán Hinds as Mance Rayder, the King-Beyond-the-Wall, the leader of all the wildlings by acclamation.
- Yuri Kolokolnikov as Styr, the Magnar of Thenn.
In Pentos and Vaes Dothrak
- Harry Lloyd as Viserys Targaryen, an exiled Targaryen claimant to the Iron Throne.
- Emilia Clarke as Daenerys Targaryen, Viserys's younger sister.
- Iain Glen as Ser Jorah Mormont, a knight of Westeros, exiled by Lord Eddard Stark.
- Jason Momoa as Khal Drogo, a warlord of the Dothraki.
- Roger Allam as Illyrio Mopatis, a magister of the Free City of Pentos.
- Dar Salim as Qotho, one of Drogo's bloodriders.
- Ivailo Dimitrov as Mago, a Dothraki warrior.
- Elyes Gabel as Rakharo, a Dothraki warrior in Daenerys's service as a bodyguard.
- Steven Cole as Kovarro, a Dothraki warrior.
- Amrita Acharia as Irri, a handmaiden gifted to Daenerys.
- Roxanne McKee as Doreah, a servant and adviser gifted to Daenerys.
- Sarita Piotrowski as Jhiqui, a handmaiden gifted to Daenerys.
- Rania Zouari as a Pentoshi servant in Illyrio's manse.
- Simon Lowe as a wineseller in Vaes Dothrak.
- Mia Soteriou as Mirri Maz Duur, a healer of the Lhazareen people.
- Nonso Anozie as Xaro Xhoan Daxos, a merchant lord of Qarth.
- Ian Hanmore as Pyat Pree, a warlock of Qarth.
- Laura Pradelska as Quaithe, a priestess of the Shadow Lands resident in Qarth.
- Nicholas Blane as the Spice King, the leader of the spice merchants of Qarth.
In Astapor and Yunkai
- Nathalie Emmanuel as Missandei, a slave and translator working in the city of Astapor.
- Dan Hildebrand as Kraznys mo Nakloz, a slave-trader and immensely rich merchant in Astapor.
- Ramon Tikaram as Prendahl na Ghezn, a mercenary commander.
- Ed Skrein (Season 3)/Michiel Huisman (Season 4) as Daario Naharis, a charismatic mercenary.
- Jacob Anderson as Grey Worm, a warrior-eunuch of the Unsullied.
- Joel Fry as Hizdahr zo Loraq, a lord of Meereen.
- David Benioff - writer/executive producer.
- D.B. Weiss - writer/executive producer.
- George R.R. Martin - writer/executive producer.
- Guymon Cassidy - executive producer.
- Carolyn Strauss - executive producer.
- Ralph Vincinaza - executive producer.
- Vincent Gerardis - executive producer.
- Frank Doelger - producer.
- Mark Huffam - producer
- Thomas McCarthy - director (pilot).
- Sean Bobbitt - director of photography.
- Sean Guest - 1st assistant director.
- Tatiana S. Riegel - editor.
- Gemma Jackson - production designer.
- Michele Clapton - costume designer.
- Marisa Clayton - digital post-production.
- Julia Frey - production supervisor/location scout (pilot).
- Robert Stromberg - VFX supervisor (pilot).
- Ramin Djawadi - music (series).
- Buster Reeves - stunt work (pilot).
- Corvus Corax - music (Winterfell feast scene).
- Nina Gold - London casting director.
- Amy Berman & Carrie Frazier - Los Angeles casting directors.
- Michelle Taylor Spellman - Los Angeles casting associate.
- Kerry Barden & Paul Schnee - New York casting directors.
- Allison Estrin - New York casting associate.
- David Benioff & D.B. Weiss: episodes 1-3, 5, 7, 9-12, 15, 17-18, 20-21, 23-24, 26, 28-31, 33, 35, 37-40.
- Bryan Cogman: episodes 4, 13, 25, 34 and 36.
- Jane Espenson: episode 6.
- George R.R. Martin: episodes 8, 19, 27 and 32.
- Vanessa Taylor: episode 14, 16 and 22.
- Thomas McCarthy: pilot episode (unscreened).
- Tim Van Patten: episodes 1-2.
- Brian Kirk: episodes 3-5.
- Daniel Minahan: episodes 6-8, 21-22.
- Alan Taylor: episodes 9-12, 18 & 20.
- Alik Sakharov: episodes 13, 26, 36-37.
- David Petrarca: episodes 14-15.
- David Nutter: episodes 16-17, 29-30.
- Neil Marshall: episodes 19 & 39.
- David Benioff: episodes 23.
- Alex Graves: episodes 24-25, 32-33, 38 & 40.
- Michelle MacLaren: episodes 27-28, 34-35.
- D. B. Weiss: episode 31.