Foundation season 3 cast and character guide: Who’s returning, who’s new, and who’s playing what

Foundation season 3 premiered on Friday, July 11, 2025, on Apple TV+, marking the continuation of Isaac Asimov's science fiction epic. Set 152 years after season 2, the new chapter arrives with increased stakes and the ascension of The Mule—a psychic warlord whose abilities are not only be capable of destroying the Galactic Empire but also the future of the Foundation.

With the galaxy on the edge of collapse, the cast members from season 2 are back to face their fates head-on, as a new batch of characters adds tension and political maneuverings. Let's take a look at the main and supporting cast, led by Jared Harris who plays Hari Seldon.

Main cast of Foundation season 3

Below is a comprehensive guide to the main cast members of Foundation season 3, spotlighting the actors behind the characters and what fans can expect from each role in the latest chapter of this sci-fi series.

1) Jared Harris as Hari Seldon

Jared Harris as Hari Seldon from the series (Image via YouTube/Apple TV)

Jared Harris reprises his role as Hari Seldon, the architect of psychohistory—a revolutionary science that predicts the future of large populations. Despite being long dead in physical form, Seldon continues to guide humanity through his digital consciousness. In Foundation season 3, his dynamic with Gaal Dornick evolves from secrecy and manipulation to a more collaborative and equal partnership.

Where you’ve seen him: Harris is acclaimed for his roles in Chernobyl (Valery Legasov), The Crown (King George VI), Mad Men (Lane Pryce), and The Expanse.

2) Lou Llobell as Gaal Dornick

Lou Llobell as Gaal Dornick from the series (Image via YouTube/Apple TV)

Lou Llobell returns as Gaal, Hari’s protégé and a mathematical prodigy from a repressive, anti-intellectual world. Now assuming a leadership role, she is poised to challenge The Mule’s rise while shouldering the future of Seldon's Plan.

In an interview with Gizmodo, published on July 10, 2025, Llobell described Gaal’s journey this season as a leap into becoming a "good leader," willing to risk everything. She said:

"I think she listens to her people. I think she’s inclusive. I think she allows people to be themselves."

Where you’ve seen her: Llobell made her film debut in Voyagers (2021) and is best known for her role in Foundation.

3) Laura Birn as Demerzel

Laura Birn as Demerzel from the series (Image via YouTube/Apple TV)

Laura Birn takes on the role of Demerzel again. She is a near-immortal confidant to the Cleon emperors. Though bound by ancient programming, she exhibits complex emotions like regret and love.

In Foundation season 3, she stands at the intersection of loyalty and conscience, especially as The Mule’s threat grows. During a conversation with Reactor Magazine on July 10, 2025, Birn emphasized the character’s internal conflict and her moral uniqueness among the cast. She mentioned:

"But what makes her different is that she doesn’t operate from a place of ego."

Where you’ve seen her: Birn has starred in The Crow (2024), A Walk Among the Tombstones, and Netflix’s The Innocents.

4) Lee Pace as Brother Day

Lee Pace as Brother Day from the series (Image via YouTube/Apple TV)

Lee Pace returns to the series, portraying Brother Day. He is the ruling clone of Emperor Cleon, representing the Empire’s present. As his grip on power weakens and his behavior grows erratic, he enters a more selfish, hedonistic phase.

In the same interview with Reactor Magazine, Pace described his character’s arc this season as a rebellion against the crushing expectations of leadership. He highlighted that Brother Day "doesn’t care about holding control and power."

Where you’ve seen him: Pace is known for Pushing Daisies, Halt and Catch Fire, and the MCU’s Guardians of the Galaxy (Ronan the Accuser).

5) Terrence Mann as Brother Dusk

Terrence Mann as Brother Dusk from the series (Image via YouTube/Apple TV)

In Foundation season 3, Terrence Mann reprises his role as Brother Dusk. He is the elder clone and former Emperor, now serving as an advisor and historical archivist. He’s determined to safeguard the Empire’s legacy at all costs. His experience brings wisdom, but also inflexibility, setting him at odds with younger clones and the shifting galaxy.

Where you’ve seen him: With an extensive experience on Broadway, television, and film, Mann is best recognized for Sense8, The Dresden Files.

6) Cassian Bilton as Brother Dawn

Cassian Bilton as Brother Dawn from the series (Image via YouTube/Apple TV)

Cassian Bilton returns as the youngest Cleon clone, Brother Dawn, who is destined to become the next Day. In Foundation season 3, he begins to chafe under the system’s constraints, developing an independent streak that challenges the Empire’s rigid succession.

Where you’ve seen him: Foundation is Bilton’s breakout role, with prior appearances in the short film Shoal.

7) Pilou Asbæk as The Mule

Pilou Asbæk as The Mule from the series (Image via YouTube/Apple TV)

A terrifying new force, in Foundation season 3, The Mule is a powerful mutant with psychic abilities capable of altering minds and destroying the Plan. Although a recast happened for the character from Mikael Persbrandt (who appeared in season 2), now Asbæk brings the character fully into focus after a mysterious season 2 tease. His version of The Mule comes with trauma, charisma, and a dangerous ambition.

Where you’ve seen him: Asbæk is known for Game of Thrones (Euron Greyjoy), Borgen, Ghost in the Shell, and Aquaman and the Lost Kingdom.

New supporting cast of Foundation season 3

Troy Kotsur as Preem Palver- A leader among telepaths, Palver is a key ally in the resistance against The Mule. Kotsur’s use of sign language stands out in the show.
Synnøve Karlsen as Bayta Mallow- A freedom fighter and descendant of a legendary Foundation family, Bayta joins the battle against The Mule’s psychic manipulation.
Cody Fern as Toran Mallow- Bayta’s husband and partner in rebellion. Together, they represent the new generation of resistance.
Tómas Lemarquis as Magnifico Giganticus- A strange performer with mysterious ties to The Mule. His true identity could upend the entire balance of power.
Leo Bill as Mayor Indbur- The bureaucratic leader of Terminus, trying to maintain order in an increasingly unstable galaxy.

Catch the latest episode of Foundation season 3 currently streaming on Apple TV.

About the author

Ankur Pandey covers all things pop culture and entertainment at Sportskeeda. He holds a Postgraduate Diploma in Mass Communication from St. Xavier's College in Mumbai, which has equipped him with exceptional storytelling, and communication skills. With over a year of experience as a news anchor & producer at ITV Network, Ankur has interviewed notable Indian celebrities including, Anu Malik and Shalin Bhanot. His insightful coverage of environmental issues also earned him further recognition.

His fascination with media trends and their profound impact on society ignited his passion for working in the dynamic entertainment industry while ensuring ethical reporting through thorough research. On a personal level, Ankur admires the versatility and environmental advocacy of Leonardo DiCaprio, and would choose to experience The Lord of the Rings trilogy for its monumental cinematic journey.

In his free time, Ankur enjoys reading to gain new perspectives and traveling to immerse himself in diverse cultures, all while keeping an active lifestyle.

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Edited by DEEPALI