HBO's main cast of Mountainhead is absolutely fantastic, and here is who they all are.

HBO's Mountainhead comes from Jesse Armstrong, the creator of the critically acclaimed HBO series Succession. The film follows four billionaire friends who go on a retreat to a secluded mountain lodge while financial, political, and technological disasters ruin the world. While there, the friends attempt to figure out how to use the disasters to line their pockets, leading to conflicts between the group. Mountainhead has a lot of similarities to Succession, meaning that fans of the HBO series need to check out Jesse Armstrong's newest project now that it is streaming.

Steve Carell As Randall

Born On August 16, 1962

• Active Since: 1989

Actor: Steve Carell was born on August 16, 1962, in Concord, Massachusetts, and started acting in commercials and comedy troupes before getting his big break as a cast member on The Dana Carvey Show. Steve Carell worked on several high-profile projects in the early 2000s, such as The Daily Show with Jon Stewart, Anchorman: The Legend of Ron Burgandy, The 40-Year-Old Virgin, and more. In 2005, Carell got even bigger thanks to his starring role in the iconic sitcom The Office. From there, he continued acting in comedy projects before beginning to take on more serious roles in the mid-2010s.

Notable Movies/TV Shows

Character: In Mountainhead, Steve Carell plays Randall, the oldest of the tech billionaires in the friend group. At the start of the film, he is the richest member of the four, with him taking on a position of leadership among the others. However, he struggles to hold onto this role as things spiral out of control.

Jason Schwartzman As Hugo Van Yalk

Born On June 26, 1980

• Active Since: 1994

Actor: Jason Schwartzman was born on June 26, 1980, in Los Angeles, California, and had his big break with his film debut in Wes Anderson's 1998 movie Rushmore. Since then, Schwartzman has become a frequent collaborator of Anderson, appearing in The Darjeeling Limited, Fantastic Mr. Fox, Moonrise Kingdom, The Grand Budapest Hotel, The French Dispatch, and Asteroid City. Schwartzman has appeared in other acclaimed movies like Scott Pilgrim vs. the World and Spider-Man: Across the Spider-Verse, as well as TV shows like Fargo.

Notable Movies/TV Shows

Character: In Mountainhead, Jason Schwartzman plays Hugo Van Yalk, the owner of the titular lodge. Despite his massive home, Hugo is the poorest of the billionaires, something that often gets him made fun of. Because of this, he hopes to win the approval of Steve Carell's Randall as well as the other characters, something that drives many of his decisions throughout the film.

Cory Michael Smith As Venis

Born On November 14, 1986

• Active Since: 2009

Actor: Cory Michael Smith was born on November 14, 1986, in Columbus, Ohio, with him getting his start in theater plays while attending Otterbein University. He continued acting in plays, with him making his Broadway debut in a 2013 production of Breakfast at Tiffany's, and then making his feature film debut in 2014's Camp X-Ray. Smith's career really took off when he landed the role of Edward Nygma, a.k.a The Riddler, in the television series Gotham. He has also become a frequent collaborator of director Todd Haynes, appearing in Carol, Wonderstruck, and May December.

Notable Movies/TV Shows

Character: In Mountainhead, Cory Michael Smith plays Venis, the Elon Musk parody within the group. Venis is behind an AI company that plays a major hand in the world chaos that acts as the backdrop of Mountainhead.

Ramy Youssef As Jeff

Born On March 26, 1991

• Active Since: 2009

Actor: Ramy Youssef was born on March 26, 1991, in New York City, New York, with him making his acting debut on the Nick series See Dad Run. While doing stand-up comedy, Youssef continued acting and writing, with him eventually creating his TV show Ramy, which premiered on Hulu in 2019. Youssef later co-created the series Mo, which ran from 2022 to 2025. The actor has also performed in projects like Why Him?, Mr. Robot, Don't Worry, He Won't Get Far on Foot, Poor Things, and Wish. Youssef also directed the episode of The Bear "Honeydew" as well as several other projects.

Notable Movies/TV Shows

Character: In Mountainhead, Ramy Youssef plays Jeff, another member of the friend group of billionaires. Jeff is more antagonistic towards their business practices than his friends, with him acknowledging that their products are hurting the world. This leads to a divide between him and the other three billionaires, kicking off the plot of Mountainhead.

Mountainhead ing Cast & Characters

Who Else Is In The Movie

Although Steve Carell, Jason Schwartzman, Cory Michael Smith, and Ramy Youssef make up the main cast of Mountainhead, they aren't the only actors who appear in the film. Various family and Mountainhead employees make small appearances in the movie, although the film mostly focuses on the main quartet of billionaires.

Mountainhead also features Hadley Robinson as Hester, Andy Daly as Casper, Ali Kinkade as Berry, Daniel Oreskes as Dr. Phipps, David W. Thompson as Leo, Amie MacKenzie as Janine, and Ava Kostia as Paula. The star-studded cast of Mountainhead brings these characters to life, turning the film from a dialogue-heavy bottle movie to a spectacle full of biting satire and hilarious moments.