| Thomas Middleditch | Richard Hendricks |
| T.J. Miller | Erlich Bachman |
| Josh Brener | Nelson 'Big Head' Bighetti |
| Martin Starr | Bertram Gilfoyle |
| Kumail Nanjiani | Dinesh Chugtai |
| Amanda Crew | Monica Hall
(credit only) |
| Zach Woods | Donald 'Jared' Dunn |
| Matt Ross | Gavin Belson |
| Suzanne Cryer | Laurie Bream
(credit only) |
| Jimmy O. Yang | Jian Yang |
| Frank Collison | Noah |
| Andy Daly | Doctor
(as Andrew Daly) |
| Patrick Fischler | Dr. Davis Bannercheck |
| Aly Mawji | Aly Dutta |
| Adam Ray | |
| Brian Tichnell | Jason |
| Alice Wetterlund | Carla Walton |
| Diane Chernansky | Heidi Evans |
| Arthur Keng | Nucleus Engineer #1 |
| Casey O'Farrell | Nucleus Engineer #2 |
| Blake Sheldon | App Developer |
| Amra Silajdzic | Jelena |
| Benjamin Pitz | Hooli Nucleus Programmer
(uncredited) |
| Joe Spellman | Bannerchecks's Guy
(uncredited) |
| Paul Zecharia | Hooli Employee
(uncredited) |