AJ is a 17-year-old aspiring comedy writer living in the small town of Gladstone, Massachusetts. Sidelined by a broken arm that ruins her athletic scholarship prospects, she feels trapped in her local environment and uses sharp, self-deprecating humor as a defense mechanism. She escapes her volatile home life by writing fan fiction about the cult-classic series Astronauticals.

Noah is a 21-year-old heir to a formidable American acting dynasty who returns to Gladstone to oversee his mother's medical care. He maintains a brooding, intensely guarded exterior to cope with his family's chaotic legacy and his mother's severe illness. Seeking an escape from his circumstances, he relies on his extensive knowledge of improvisational theater to process his grief.

Eudora is a Tony- and Emmy-winning actress and the formidable matriarch of the Drew family. Despite her imperious and critical demeanor, she harbors deep grief over the loss of her longtime creative and romantic partner. She serves as an intense, demanding mentor to the younger generation, fiercely protecting her family's artistic legacy.

Jack is AJ's father, a controlling man whose alcohol addiction dictates the emotional climate of the Graves household. His sudden rages and volatile moods force his children into rigid coping roles. He frequently directs demeaning comments toward his family members.

Katie is AJ's mother, a passive presence in the Gladstone home. She operates as an enabler for her husband's alcohol addiction by maintaining a strict code of silence. She avoids direct confrontation regarding the family's dysfunction.

Patrick is AJ's older brother, a successful college athlete who holds the status of the family's golden boy. He often acts as a protective shield for his younger siblings against their father's temper. He holds strong, traditional opinions about AJ's social circle and choices.

Libby is AJ's 19-year-old older sister. A former head cheerleader at Gladstone High, she possesses a bossy personality that contrasts with AJ's defensive humor. She often judges her siblings' life choices based on conventional standards of success.

Emily is AJ's twin sister, who has Down syndrome. She provides a grounding force of unconditional love within the otherwise tense Graves household. Her honest, unguarded emotional presence sharply contrasts with the performative defenses her family members maintain.

Mike is AJ's 15-year-old younger brother, an avid gamer who shares AJ's interest in niche subcultures. He frequently stirs trouble at home but acts as a catalyst for AJ's social interactions by volunteering her and Noah for community events.

Elle is Patrick's wife. She provides a steady, empathetic foundation for her husband and extended family. Her practical approach to caregiving and marriage offers AJ a new perspective on long-term commitment.

Toni is an actor and improviser who collaborates closely with AJ in New York. She harbors an intense desire for fame and industry recognition. Her ambition sometimes creates professional jealousy and tension within her friendships.

Dave is AJ's roommate and an exceptionally talented improviser at the Upright Citizens Brigade. He operates as a steadfast, uncomplicated friend who helps AJ navigate the professional comedy scene.

Ian is a veteran executive producer and AJ's industry mentor. While he encourages her career, he remains highly pragmatic and self-serving, prioritizing the success of his television projects over personal loyalty to his staff.

Em is a powerful television creator and director. He leverages an impending writers' strike to launch a reality-based prequel project, running his sets with tight control and unpredictable social dynamics.

Storm owns Reel World Video in Gladstone, managing AJ and hiring Noah for the summer shift. She oversees the mundane retail environment where the protagonists first connect.

Lorraine is Noah's mother, a woman facing a grave, incurable neurological disorder. She resides in a care facility near Gladstone, maintaining her sharp wit despite her physical deterioration.

Daniel is Noah's absentee father, a narcissistic figure within the Drew acting dynasty whose failures drove Noah away from his family roots.

Ezell is Eudora's late partner and Noah's great-uncle. A comedy legend, he authored a foundational book on improvisational theater that profoundly influences the younger characters.

Brian is a 28-year-old sports reporter based in New York. He possesses an affable, straightforward personality that offers a stable, uncomplicated alternative to the volatile entertainment industry.

Allison is an actress who works within Noah's professional sphere as his career advances in Hollywood. She operates within the high-stakes world of public relations and major film releases.

Bud is a puppy that Noah adopts at Drew House. The dog remains a loyal, constant companion to Noah through various personal and professional changes.

Peter chairs a local science fiction society and organizes fan events. He facilitates the initial convention panel that sets the protagonists' acting journey in motion.

Mrs. Gilroy is the housekeeper at Drew House. She remains deeply protective of the estate and displays open disdain toward outsiders visiting the property.

Anjalee is a famous pop star hired to act in a major television project, bringing immense celebrity status to the set. Her presence creates tension and competition among the lesser-known actors.

Elmore is a veteran actor returning to a science-fiction franchise he helped launch decades earlier. He uses humor and flirtation to assert his veteran status on set.

Todd is an unpaid intern tasked with logging massive amounts of unscripted footage for a reality television production. He serves as an early audience for the raw emotional performances captured on set.

Leah is an actor cast in the role of a ship's doctor for a new sci-fi series. She participates in the immersive filming environment created by the producers.

Andy is a performer hired to play a brute character in an unscripted prequel show. He works alongside the rest of the ensemble to generate spontaneous scenes.

Dani serves as the head writer for a major late-night sketch comedy show in New York. She demands quick thinking and discipline from her writing staff.

Molly works as a literary agent, leveraging her industry knowledge to secure better contracts for her clients. She helps protect writers from exploitative television producers.

Risa is a publicist tasked with managing the public image and convention appearances of high-profile actors. She attempts to enforce strict boundaries to protect her clients' reputations.

Ned works as a talent manager in Hollywood, operating alongside his wife, Risa, to guide celebrity careers through major film campaigns.

Oona is a dedicated super-fan and co-chair of a society devoted to celebrating specific science-fiction media. She uses her enthusiasm to organize massive events for the community.

Otto operates alongside Oona to organize massive fan conventions and support online fandom communities. He manages the financial logistics of large-scale fan events.

Meagan is a preteen fan who finds personal strength through the fictional characters depicted in her favorite television show. Her genuine emotional response highlights the real-world impact of the cast's work.

Xiaobo is an improvisational comedian trained at Second City who performs in New York jam sessions. He participates in the competitive comedic environment where major casting decisions are made.

Charlie is Patrick and Elle's young son. His safety remains a primary concern for his parents during a devastating family crisis.

Claire is Patrick and Elle's infant daughter. Her presence brings a sense of normalcy and chaotic joy to the family during a period of recovery.

Lucas is Libby's husband, fitting into the conventional life expectations of the Gladstone community. His marriage eventually faces intense scrutiny as his wife reevaluates her choices.