Stiller surrounded Scott with a roster of talented and accomplished actors. John Turturro and Zach Cherry play his MDR co-workers Irving and Dylan, and Britt Lower plays Helly, the newest addition to their team. Burt Goodman (Christopher Walken) works elsewhere in the building in Lumon's research department, and all of them fall under the piercing watchful eye of Lumon boss Harmony Cobel (Patricia Arquette).
Scott told the Los Angeles Times that he was initially intimidated when he learned who he would be working with on the set of "Severance," thinking "Oh, my God, I really need to know what I'm doing here." Of Arquette, he said, "When you're working with Patricia, you are watching someone who is totally fearless. She's unbelievably well prepared, but she's also good enough to know that once you're there and the camera's rolling, it's time to throw all that out and just experiment. Every time I had a scene with Patricia, I got up and ran a little faster to work that day."
Stiller said his prior experience working with Arquette had also keyed him into what would make her a good fit for the role of Harmony Cobel. "She has so much going on and she can do very little and be so fascinating and so intimidating," Stiller said. "She was one of the first people I thought of also."
