Complete cast breakdown of All Her Fault Season 1: Who plays who & where you’ve seen them before

Megan Gallagher’s new mystery thriller, All Her Fault season 1, is set to premiere on November 6, 2025, on Peacock. The show is based on the novel of the same name by Andrea Mara. Directed by Minkie Spiro and Kate Dennis, the series ensemble includes Succession star Sarah Snook, who becomes entangled in a mystery involving her missing son, Milo. 

Milo goes missing when she heads to pick him up after the playdate. When she reaches 14 Arthur Avenue to pick up her son, no one knows who she is or where her son is. Completely shocked and confused, Marissa realizes something is terribly wrong. What begins as a simple misunderstanding quickly turns into a tense mystery involving lies, secrets and hidden connections between families. As Marissa searches desperately for her missing child, she uncovers disturbing truths about the people around her and even begins to question whom she can really trust.

The official synopsis of All Her Fault season 1 reads,

“Marissa Irvine arrives to collect her young son Milo from his first playdate, but the woman who answers the door isn’t a mother she recognizes. She doesn’t have Milo and has never heard of him. As every parent’s worst nightmare begins to unfold, new questions lead to deep secrets, revealing cracks in the Irvine’s seemingly perfect world until everything is left shattered.”

Complete cast breakdown of All Her Fault season 1

Sarah Snook plays Marissa Irvine

She takes on the lead role in All Her Fault season 1. Starring as Marissa Irvine, she is Milo’s mother, who is desperately searching for him. Sarah Snook is a familiar face from HBO’s hit series, Succession, where she plays Shiv Roy, and that role helped her win an Emmy. She has also worked in several Australian TV series, like The Beautiful Lie and Sisters of War. She also appeared in one of the episodes of Black Mirror as Medina (a military squad leader). Some of Snook's best works feature Run Rabbit Run, Pieces of a Woman, Memoir of a Snail and more.

Jake Lacy plays Peter Irvine

In All Her Fault season 1, Jake Lacy plays Peter Irvine, Marissa’s husband and Milo’s father. Just as Marissa’s life has turned upside down, Peter, too, gets caught up in the “worst nightmare a parent could ever have.” But mystery holds within every character, and what secrets lie behind him are awaited to be seen. 

Jake has a commendable career in the acting industry, and fans must have seen him in the very first season of The White Lotus, where he appeared as Shane. With that, he even starred in the sitcom comedy, The Office, as Pete Miller, “a new guy who challenged Andy Bernard.” Better With You, Apple Never Fall, Obvious Child, Girls, and A Friend of the Family are some of his projects in which he previously worked.

Dakota Fanning plays Jenny

In All Her Fault season 1, Fanning plays Jenny, a mother who knows Marissa Irvine through their children, who attend the same school. The actress achieved her breakthrough role as a child actor in I Am Sam, for which she earned a Screen Actors Guild Award nomination at the age of seven. Man on Fire, War of the Worlds, The Twilight Saga, and Once Upon A Time in Hollywood are some of her best works.

Michael Peña as Detective Alcaras

Michael plays the character of a detective in All Her Fault season 1, who joins the dots about Milo’s disappearance. Starred in Crash and Million Dollar Baby, the actor even appeared in Netflix’s Narcos: Mexico, where he played DEA agent Kiki Camarena. He has worked in films like World Trade Center (2006), End of Watch (2012), American Hustle (2013), and The Martian (2015). The actor was even a part of the Marvel Universe, where he played Luis in Ant-Man (2015) and Ant-Man and the Wasp (2018).

Sophia Lillis as Carrie Finch

Sophia, in All Her Fault season 1, plays the character of Carrie Finch. Her character is said to appear in the series as quite “mysterious.” Sophia starred in the hit horror franchise “It” (2017) and “It: Chapter Two” as Beverly Marsh, and she was also a member of “The Losers Club.” Nancy Drew and the Hidden Staircase, Gretel and Hansel, Uncle Frank, and Netflix’s I am Not Okay With This are some of her best works. Recently, she appeared in the ongoing HBO show, The Chair Company. 

Abby Elliott as Lia Irvine

A family member of Irvines, she is Peter’s sister and Milo’s aunt in All Her Fault season 1. The actress was a cast member of SNL, and for her role in The Bear, Abby was nominated for a Golden Globe for playing Natalie "Sugar" Berzatto. How I Met Your Mother, Odd Mom Out, Cheaper by the Dozen, and Indebted are some of the projects in which the actress was previously seen. 

Jay Ellis as Colin

Jay is one of the faces who has appeared in many famous series and films. However, in All Her Fault season 1, he appears as “a friend and colleague of Marissa Irvine's.” He worked in Top Gun: Maverick alongside Tom Cruise as Lt. Reuben “Payback” Fitch. Jay has also appeared in films like Escape Room, A Boy. A Girl. A Dream, and Freaky Tales. He even made guest appearances on TV series such as Grey’s Anatomy, NCIS, How I Met Your Mother and more. 

Daniel Monks as Brian Irvine

Part of the Irvine family, Daniel Monks plays Brian Irvine, Peter’s and Lia’s brother, who finds himself drawn into the tense investigation surrounding Milo’s disappearance. Netflix’s Kaos and Dead Hot are some of the TV series in which he appeared, and A Knight of the Seven Kingdoms is his upcoming project, where he will play Ser Manfred Dondarrion. 

Duke McCloud as Milo Irvine

The child actor, who goes missing in the show, is played by Duke in All Her Fault season 1. He made his screen debut in the 2025 Amy Schumer comedy Kinda Pregnant.