| Thomas Middleditch | Richard Hendricks |
| 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 |
| Suzanne Cryer | Laurie Bream |
| Jimmy O. Yang | Jian Yang |
| Chris Diamantopoulos | Russ Hanneman
(credit only) |
| Sunkrish Bala | Garrett |
| Arturo Castro | Maximo Reyes |
| Helen Hong | Tracy Robertson |
| Bernie Kopell | Lex Skelton |
| David Rees Snell | Ross Loma Capital Executive |
| Bernard White | Denpok |
| Chris Williams | Hoover |
| Scott Prendergast | Scott |
| Rogelio T. Ramos | Executive |
| Nandini Bapat | Gwart |
| David Bickford | Vaughn |
| Pete Punito | Eric Rivera |
| David Pevsner | Ad Guy |
| Lou Richards | Lee |
| Alessandro Pedrazzi | Fundraiser Guest
(uncredited) |
| Sam Vaghani | Pied Piper Engineer
(uncredited) |