1999 | King and Me, TheThe King and Me | Tukang antar pizza | |
Flushed | Pria menyedihkan | |
2001 | Heartbreakers | Bill | |
Bubble Boy | Penjaga halte | |
Corky Romano | Dexter | |
Out Cold | Luke | |
2002 | Late World with Zach | Pembawa acara | 29 episode |
Below | Weird Wally | |
2003–2005 | Tru Calling | Davis | 26 episode |
2004 | Zach & Avery of Fergus | Tunawisma | |
2005 | The Comedians of Comedy | Diri sendiri | |
2006 | Pity Card, TheThe Pity Card | Zach | |
Dog Bites Man | Alan Finger | 9 episode |
2007–2010 | Tim and Eric Awesome Show, Great Job! | Tairy Greene | 7 episode |
2006–2007 | Zach Galifianakis Live at the Purple Onion | Diri sendiri / Seth Galifinakis | Penulis dan produser eksekutif |
2007 | Into the Wild | Kevin Wallis | |
2008 | What Happens in Vegas | Dave si beruang | |
Super High Me | Diri sendiri | Dokumenter |
Visioneers | George | |
2009 | The Ballad of G.I. Joe | Snow Job | |
Gigantic | Tunawisma | |
Hangover, TheThe Hangover | Alan Garner | - MTV Movie Award for Best Comedic Performance
- Nominasi – Houston Film Critics Society Award for Best Supporting Actor
- Nominasi – MTV Movie Award for Best Breakthrough Performance
|
2009–2010 | American Dad! | Heavyset man / Norman / Juror | 2 episode (alih suara) |
2009–2011 | Bored to Death | Ray | 24 episode |
2009 | G-Force | Ben Paredes | |
Up in the Air | Steve Sewa | |
Operation: Endgame | Hermit | |
Little Fish, Strange Pond | Bucky | |
2010 | Youth in Revolt | Jerry | |
Frenemy | Penjaga toko dewasa | |
Dinner for Schmucks | Therman Murch | Comedy Award – Best Comedy Actor in Film |
It's Kind of a Funny Story | Bobby | |
Due Date | Ethan Tremblay / Ethan Chase | Nominasi – MTV Movie Award for Best Comedic Performance Nominasi – Teen Choice Awards for Choice Movie: Actor Comedy |
2010–2013 | Saturday Night Live | Diri sendiri | 3 episode Nominasi – Primetime Emmy Award for Outstanding Guest Actor in a Comedy Series (2011) |
2011 | Hangover Part II, TheThe Hangover Part II | Alan Garner | Nominasi – MTV Movie Award for Best Comedic Performance Nominasi – Teen Choice Awards for Choice Movie: Actor Comedy Nominasi – Teen Choice Awards for Choice Movie: Chemistry (shared with Bradley Cooper and Ed Helms) |
Puss in Boots | Humpty Dumpty | Alih suara Nominasi – Annie Award for Best Voice from an Animated Feature |
The Muppets | Hobo Joe | |
2012 | Tim and Eric's Billion Dollar Movie | Jim Joe Kelly | |
The Campaign | Marty Huggins | Nominasi - MTV Movie Award for Best On-Screen Duo (bersama Will Ferrell) |
Bob's Burgers | Chet | |
2013 | The Hangover Part III | Alan Garner | |
You Are Here | Ben | Pasca-produksi |
2014 | Birdman | | Produksi |