Green Man has evolved into a 25,000 capacity week long event, showcasing predominantly live music (in particular alternative, indie, rock, folk, dance and Americana).

Previous headliners have included Kraftwerk, Bicep, Laura Marling, Van Morrison, Michael Kiwanuka, PJ Harvey, Fontaines D.C, Devo, Fleet Foxes and First Aid Kit.

[11] Notable acts included: Big Thief, Sampha, Jon Hopkins, Sleaford Mods, Arlo Parks, Explosions In The Sky, Devendra Banhart, The Jesus & Mary Chain and Ezra Collective.

Devo, First Aid Kit, Self Esteem, Spiritualized, Amyl & The Sniffers, Slowdive, Young Fathers, The Walkmen, Confidence Man, Goat, The Comet Is Coming, Squid, Lankum, Horace Andy ft. Dub Asante Band, Sudan Archives, Snail Mail, Jockstrap, Warmduscher, Gilla Band, Les Savy Fav, The Delgados, The Wedding Present, Beth Orton, Obongjayar, Billy Nomates, Bob Vylan, Daniel Avery (live), Dur-Dur Band Int., Courtney Marie Andrews, Buck Meek, James Holden, Sorry, PVA, Clipping., Girl Ray, Julie Byrne, Lost Map presents Weird Wave, Rozi Plain, Alabaster Deplume, Kanda Bongo Man, Special Interest, Gina Birch, Jake Xerxes Fussell, Anna B Savage, Cory Hanson, Etran D’el Air, The Orielles, Melin Melyn, The Bug Club, Josephine Foster, Christian Lee Hutson, Sarah Jarosz, Say She She, James Ellis Ford, Marie Davidson DJ, Arushi Jain, H. Hawkline, Crows, Water From Your Eyes, Floodlights, Julie, Thus Love, Plastic Mermaids, Alice Boman, Salami Rose Joe Louis, Nuha Ruby Ra, Spencer Cullum, deathcrash, Yasmin Williams, Aoife Nessa Frances, Oscar Lang, Mega Bog, Σtella, Eaves Wilder, Gently Tender, Fat Dog, MADMADMAD, Hagop Tchaparian, Deptford Northern Soul Club, 4am Kru, Free Love, Drahla, The Gentle Good, Etta Marcus, Sans Soucis, Sister Wives, Sam Akpro, Brad Stank, Bricknasty, Juni Habel, Clara Mann, DD Darillo, Aisha Vaughan, Rogue Jones, Butch Kassidy, Cumgirl8, Freak Slug, Hyll, Island of Love, Joyeria, Lady Maisery, The Last Dinner Party, Lilo, Mandy, Indiana, Mary in the Junkyard, Minor Conflict, Morgon Noise, Oslo Twins, The Outlines, Pencil, Seb Lowe, Spielmann, Suep, uh, University, Yabba, Ziyad Al-Samman Kraftwerk, Michael Kiwanuka, Beach House, Metronomy, Bicep (live), Parquet Courts, Low, Kae Tempest, Cate Le Bon, Ty Segall & Freedom Band, Ezra Furman, Dry Cleaning, Tune-Yards, Yves Tumor, Black Country, New Road, Jenny Hval, Arab Strap, Valerie June, Alex G, Arooj Aftab, Viagra Boys, Mdou Moctar, Orchestra Baobab, The Murder Capital, Witch, Mary Lattimore, Jessie Buckley & Bernard Butler, Willie J Healey, Frazey Ford, Torres, Donny Benét, BCUC, Charlotte Adigery & Bolis Pupul, Nia Archives, Carwyn Ellis & Rio18 w/BBC National Orchestra of Wales, Ichiko Aoba, Sofia Kourtesis, Optimo (Espacio), Lone, Nathan Fake (live), Lice, Psychedelic Porn Crumpets, Scalping, Cassandra Jenkins, Sugar Candy Mountain, Wesley Gonzalez, James Yorkston & Second Hand Orchestra, Katy J Pearson, John Francis Flynn, Pip Blom, Pictish Trail, Penelope Isles, Minyo Crusaders, Marisa Anderson & William Tyler, Ural Thomas & The Pain, El Goodo, Modern Nature, Planningtorock, Balimaya Project, Prima Queen, Group Listening, Keeley Forsyth, Soccer96, Charles Watson, Art School Girlfriend, Grove, Indigo De Souza, Gretel Hanlyn, Bess Atwell, Cola, Gotts Street Park, Ethan P. Flynn, Naima Bock, Annie Hart, Adwaith, Elanor Moss, John Mouse, Maria Somerville, Strawberry Guy, Katherine Priddy, Melin Melyn, Wunderhorse, The Umlauts, Keg, Honeyglaze, Mandrake Handshake, Lucy Gooch, Sophie Jamieson, Jessica Winter, Pregoblin, Brian Destiny (Dash The Henge), Papur Wal, Maria BC, Rhodri Davies, Cerys Hafana, Eli Smart, Dactyl Terra, Ailsa Tully, Alice Low, Bingo Fury, Blue Bendy, Bonnie Kemplay, Deathcrash, English Teacher, Joe & The Shitboys, Kathleen Frances, Lemondaze, Lime Garden, M(h)aol, Mickey Callisto, Pushpin, Preen Porij, Robocobra Quartet, Tapir!, Tara Clerkin Trio, Tenderhost, The Deep Blue, Unschooling

Mogwai, Caribou, Fontaines D.C, Tirzah, Thundercat, Teenage Fanclub, Django Django, This Is The Kit, Jose Gonzalez, Gruff Rhys, The Staves, Nadine Shah, Black Midi, Shame, Lump, Kokoroko, BC Camplight, Nubya Garcia, Self Esteem, Richard Dawson, Kelly Lee Owens, Ghost Poet, Greentea Peng, Georgia, Snapped Ankles, Goat Girl, Billie Marten, Erland Cooper, Catrin Finch & Seckou Keita, Gwenno, Vanishing Twin, Porridge Radio, Viagra Boys, Working Men's Club, Boy Azooga, Ross From Friends (live), The Orielles, Matt Maltese, Emma-Jean Thackray, Pictish Trail, The Surfing Magazines, Peggy Sue, Yazmin Lacey, Overmono, Los Bitchos, Big Joanie, Jockstrap, Crack Cloud, Giant Swan, DJ Rap, Stephen Fretwell, Hen Ogledd, Alabaster DePlume, Falle Nioke, Liz Lawrence, Wu-Lu, Katy J Pearson, Steam Down, PVA, Sinead O'Brien, Phoebe Green, NewDad, King Hannah, Hak Baker, H.Hawkline, Loraine James, Hannah Holland, Sarathy Korwar, Deep Throat Choir, Broadside Hacks, Fenne Lily, Ed Dowie, Buzzard Buzzard Buzzard, Peaness, Home Counties, Yard Act, The Lounge Society, Wet Leg, Matilda Mann, Gwenifer Raymond, Studio Electrophonique, Tony Njoku, LYR, John, The Golden Dregs, Deliluh, The Cool Greenhouse, Speedboat, Blood Wizard, Bugs, Caroline, Do Nothing, Drug Store Romeos, Duski, Egyptian Blue, Iwan Rheon, The Goa Express, Gonhill, Hanya, Laundromat, Lazarus Kane, Martha Skye Murphy, Melin Melyn, Modern Woman, Nuha Ruby Ra, Panic Shack, Pet Deaths, Prima Queen, Roscoe Roscoe, Sister Wives, Teddy Hunter, Tina, Alfresco Disco, Art School Girlfriend DJ, Big Jeff, Birthday Club, Charlotte Church's Late Night Pop Dungeon, Deptford Northern Soul Club, Dutty Disco, Hot Singles ClubA Certain Ratio, Adwaith, Aidan Moffat & RM Hubbert, Aldous Harding, Alex Rex, Alfresco Disco, Amadou & Mariam, Anais Mitchell, Anna St Louis, Arlo Day, Art School Girlfriend, Audiobooks, Avi Buffalo, Beabadoobee, Bess Atwell, Big Thief, Bill Ryder-Jones, Black Country, New Road, Bodega, Bridget St John, Brigid Mae Power, Callum Easter, Car Seat Headrest, Chappaqua Wrestling, Chelou, Chloe Foy, Deptford Northern Soul Club, DJ Big Jeff, Dry Cleaning, Durand Jones & The Indications, Dutty Disco, Eels, Eitha Da, Ex:Re, Ezra Collective, Father John Misty, Fever Club, Four Tet, Foxwarren, George Ogilvie, Greg Wilson, Grimm Grimm, Gwenifer Raymond, Gwenno, Hand Habits, Heavenly Jukebox, Hen Ogledd, Idles, James Heath, James Yorkston, Jerry, Jesca Hoop, Jockstrap, Johanna Samuels, John Talabot, Julia Jacklin, Just Mustard, Khruangbin, Lamb, Lee Fields & The Expressions, Malena Zavala, Mama's Broke, Mapache, Maribou State, Marika Hackman, Meggie Brown, Modern Nature, Molly Payton, N0V3L, Nilüfer Yanya, Oscar Lang, Peaness, Penelope Isles, Pet Shimmers, Pictish Trail, Pigs Pigs Pigs Pigs Pigs Pigs Pigs, Porridge Radio, Pottery, Pozi, PVA, Richard Thompson, Rosehip Teahouse, Say Sue Me, Scalping, Self Esteem, Sharon van Etten, Shy FX, Skinny Pelembe, Snapped Ankles, Sons of Kemet, Spiritcake, Squid, Squirrel Flower, Stealing Sheep, Stella Donnelly, Stereolab, Steve Mason, Tamino, The Beths, The Big Moon, The Comet is Coming, The Growlers, The Intergalactic Republic of Kongo, The Liminanas, The Mauskovic Dance Band, These New Puritans, The Wedding Present, Tim Presley's White Fence, Tiny Ruins, TVAM, Villagers, Whitney, Willie J Healey, Wych Elm, Yak, Yo La Tengo[12] Fenne Lily, The War on Drugs, Fleet Foxes, Brian Jonestown Massacre, Lemon Twigs, Teenage Fanclub, Anna Calvi, Dirty Projectors, The Wedding Present [13] PJ Harvey, Ryan Adams, Future Islands, Kae Tempest, Angel Olsen, Thee Oh Sees, Saint Etienne, Sleaford Mods, Conor Oberst, Julia Jacklin, Ride, Pictish Trail and The Big Moon.

[14] Her’s, Belle and Sebastian, James Blake, Laura Marling, Wild Beasts, Warpaint, Grandaddy, Tindersticks, Julia Holter, White Denim, Battles, BC Camplight, Unknown Mortal Orchestra, Floating Points, Ezra Furman, Michael Rother, Songhoy Blues, Jagwar Ma, Cate Le Bon, Fat White Family St Vincent, Super Furry Animals, Hot Chip, Leftfield, Slowdive, Goat, Father John Misty, Calexico, Television, Mew, Courtney Barnett, The Fall, Public Service Broadcasting, Temples, The Staves, Charles Bradley, Sun Ra Arkestra, Matthew E. White, Hunck, Beyond The Wizards Sleeve, The 2 Bears, Viet Cong, Dan Deacon, Waxahatchee, Hookworms, Marika Hackman, Emmy the Great Neutral Milk Hotel, Mercury Rev, Beirut, The Waterboys, Bill Callahan, Caribou, First Aid Kit, Slint, Nick Mulvey, The War on Drugs, Kurt Vile, Sharon Van Etten, Daughter, Poliça, Real Estate, Mac DeMarco, Panda Bear, Anna Calvi, Georgia Ruth, H. Hawkline, Sen Segur, Memory Clinic Kings of Convenience, Band of Horses, Ben Howard, Patti Smith, Fuck Buttons, Villagers, Swans, John Cale, Edwyn Collins, Stornoway, The Horrors, Midlake, Beak, Moon Duo, Parquet Courts, Phosphorescent, Jacco Gardner, Jon Hopkins, Sweet Baboo, Grass House, Roy Harper, Erol Alkan, Veronica Falls, Unknown Mortal Orchestra, Local Natives, Low, Darkstar, British Sea Power, Intermission Project, First Aid Kit Mogwai, Feist, Van Morrison, The Tallest Man On Earth, The Walkmen, Yann Tiersen, The Felice Brothers, Tune-Yards, Jonathan Richman, Dexys, Michael Kiwanuka, Cate Le Bon Fleet Foxes, Explosions In The Sky, Iron and Wine, The Low Anthem, Noah & The Whale, James Blake, Bellowhead, Villagers, Laura Marling, Robyn Hitchcock, The 2 Bears, Andrew Weatherall Doves, The Flaming Lips, Joanna Newsom, Mumford & Sons, Beirut, Billy Bragg, The Unthanks, Tindersticks, Laura Marling, Darwin Deez, John Grant, Fionn Regan, Fuck Buttons, Wild Beasts, Girls, Johnny Flynn, These New Puritans, The Tallest Man on Earth, Summer Camp, Steve Mason, "Metronomy Presents" Animal Collective, Jarvis Cocker, Wilco, Bon Iver, Wooden Shjips, British Sea Power, Errors, Grizzly Bear, Peggy Sue, Erland & The Carnival, Andrew Bird, Trembling Bells, Dirty Three Spiritualized, Super Furry Animals, Pentangle, Richard Thompson, Iron & Wine, The National, Laura Marling, Radio Luxembourg Joanna Newsom, Robert Plant, Stephen Malkmus, Devendra Banhart, Bill Callahan, Vashti Bunyan, Stephen Duffy & The Lilac Time, Battles, Seasick Steve, Gruff Rhys, Vetiver, Tunng, Steve Adey, John Renbourn, The Aliens, The Earlies Donovan, Jose Gonzalez, Calexico, Bat for Lashes, Micah P. Hinson, Jack Rose, Adem, Marissa Nadler Incredible String Band, Bonnie Prince Billy, Joanna Newsom, Adem, Wizz Jones, Tunng Green Man Festival was founded by Jo Bartlett and Danny Hagan as a 300-person one-day event at Craig-y-Nos Castle, Brecon, in 2003.

[19] Fiona increased the capacity from 15,000 to 25,000 and Green Man is currently the only major independent UK music festival to have a female director with controlling ownership.

Headline acts announced for 2020 were Caribou, Goldfrapp, Michael Kiwanuka, Mac DeMarco and Little Dragon[22] - the 2020 edition was postponed due to the COVID-19 pandemic, replaced by a digital version that year.

The Green Man Trust is the charitable wing of the festival, its aim is to create arts development programmes, training opportunities, science engagement and bring about positive change to Welsh communities.

The current ambassador for Green Man Trust is Welsh actor and musician, Iwan Rheon,[27] whose work has included Game of Thrones, Misfits and Riviera.