| Thomas Middleditch | Richard Hendricks |
| Josh Brener | Nelson 'Big Head' Bighetti |
| Martin Starr | Bertram Gilfoyle |
| Kumail Nanjiani | Dinesh Chugtai |
| Amanda Crew | Monica Hall |
| Zach Woods | Donald 'Jared' Dunn |
| Matt Ross | Gavin Belson |
| Suzanne Cryer | Laurie Bream
(credit only) |
| Jimmy O. Yang | Jian Yang |
| Chris Diamantopoulos | Russ Hanneman
(credit only) |
| Neil Casey | Colin |
| Helen Hong | Tracy Robertson |
| Aaron Sanders | Holden |
| Bernard White | Denpok |
| Chris Williams | Hoover |
| Amy Anderson | Ms. Shizaki |
| Chris Aquilino | Danny |
| Aristotle Athari | Gabe
(as Aristotle Athiras) |
| Nandini Bapat | Gwart |
| Anthony Burkhalter | Harold Gibbons |
| Cate Cohen | Melinda |
| David L. King | Mr. Hubbard |
| Andrea Lareo | Aide |
| Bill Lewis | Mr. Kleco |
| Kausar Mohammed | Nadia |
| Miguel Nájera | Board Member |
| Diallo Riddle | Paul |
| Rachel Rosenbloom | Becky |
| Krishna Smitha | Priyanka Singh |
| Steven Michael West | Business Development
(as Steve West) |
| Roman Carter | PP Coder
(uncredited) |
| Joël Dupont | Designer
(uncredited) |
| Bruce Gale | Fundraiser Guest
(uncredited) |
| Molly Malin | Hardware Engineer
(uncredited) |
| Luke Matheis | Pied Piper Coder
(uncredited) |
| Thiago Oliveira | Senator's Aide
(uncredited) |
| Alessandro Pedrazzi | Hack Hunger Guest
(uncredited) |
| Neeltarni Pratap | Office Employee
(uncredited) |
| Sam Vaghani | Formal Hack Hunger Guest /
Pied Piper Engineer
(uncredited) |