| Thomas Middleditch | Richard Hendricks |
| T.J. Miller | Erlich Bachman |
| Josh Brener | Nelson 'Big Head' Bighetti
(credit only) |
| Martin Starr | Bertram Gilfoyle |
| Kumail Nanjiani | Dinesh Chugtai |
| Amanda Crew | Monica Hall |
| Zach Woods | Donald 'Jared' Dunn |
| Matt Ross | Gavin Belson
(credit only) |
| Suzanne Cryer | Laurie Bream |
| Jimmy O. Yang | Jian Yang |
| Stephen Tobolowsky | Jack Barker
(credit only) |
| Chris Diamantopoulos | Russ Hanneman
(credit only) |
| Andy Daly | Doctor
(as Andrew Daly) |
| Ben Feldman | Ron LaFlamme |
| Joseph Bayard | Gus
(as Joseph L. Bayard) |
| Edwin R. Habacon | Oracle Security
(as Edwin H. Bravo) |
| Tim Chiou | Ed Chen |
| Irene Choi | |
| Joe Gillette | Darren |
| Allan Miller | Stuart 'Stu' Burke |
| Ryan Phillips | Jeremy |
| G. Charles Wright | Smart Refrigerator
(voice) |