‘The Staircase’ Cast on HBO Max: Who’s Playing Who?

Colin Firth Toni Collette
Tim P. Whitby/Getty Images for BFI, Phillip Faraone/Getty Images for New York Magazine

Jean-Xavier de Lestrade’s docuseries The Staircase has kept viewers hooked for more than a decade. Released in installments between 2004 and 2018, it chronicles Michael Peterson’s murder trial and its aftermath. Now it’s HBO Max’s turn to depict the morbid true-crime saga.

As we previously reported, Warner Bros’ streaming service has ordered an eight-episode adaptation of the docuseries, also titled The Staircase, written and executive-produced by Antonio Campos and Maggie Cohn.

In the forthcoming limited series, Toni Collette will play the late Kathleen Peterson, and Colin Firth will portray her husband, Michael, who was accused of her murder in a trial that made national news.

Now that we’ve streamed the docuseries version of The Staircase — the whole series is yours for the bingeing on Netflix— let’s brush up on who is playing who in the fictionalized version… that is if you don’t mind years-old spoilers from the story!

The Staircase, Series Premiere, Spring 2022, HBO Max

Toni Collette...
Phillip Faraone/Getty Images for New York Magazine

Toni Collette

Collette won an Emmy for her lead role in the Showtime comedy United States of Tara and recently returned to the small screen in Unbelievable. On the big screen, you’ve seen her in films like The Sixth Sense, Hereditary, and Knives Out.

Kathleen Peterson
Netflix

…is playing Kathleen Peterson

Kathleen, a Nortel executive and socialite in Durham, North Carolina, was found dead at the bottom of a staircase in her and Michael’s mansion on December 9, 2001, according to The Herald-Sun.

Colin Firth
Tim P. Whitby/Getty Images for BFI

Colin Firth…

Firth gave an Oscar-winning performance in the 2010 biopic The King’s Speech, and he’s also known for his roles in Bridget Jones’s Diary, Love Actually, A Single Man, and the Kingsman series.

Michael Peterson
Netflix

…is playing Michael Peterson

Michael is a Marine Corps veteran, novelist, newspaper columnist, and onetime Durham mayoral candidate who was convicted o Kathleen’s murder in 2003. Prosecutors argued he bludgeoned her to death; he claimed she fell. Michael spent years in prison before his conviction was overturned, and in 2017, he pleaded guilty to the killing in an Alford plea and walked free with time served, per WRAL.

Rosemarie DeWitt
Larry Busacca/Getty Images

Rosemarie DeWitt…

DeWitt, whose casting was announced by Deadline, starred in the TV shows Little Fires Everywhere, The Last Tycoon, United States of Tara, and Standoff (which co-starred her now-husband, Ron Livingston). On the big screen, she’s known for her roles in the films Rachel Getting Married, Poltergeist, and La La Land.

Candace Zamperini
WTVD

…is playing Candace Zamperini

Zamperini is Kathleen’s sister, who gave impassioned speeches in court throughout the Staircase saga. “You brutally took the life of a woman who provided for you [and] guarded your children. She loved you!” she told Michael at his Alford plea hearing, per the Associated Press. (By the way, Rosemarie DeWitt also played Toni Collette’s sister in United States of Tara.)

Sophie Turner
Frazer Harrison/Getty Images

Sophie Turner

Actress Sophie Turner became a breakout star through her role as Sansa Stark in HBO’s hit series Game of Thrones. She has made a splash on the big screen as Jean Grey (a.k.a. Phoenix) in 2016’s X-Men: Apocalypse and 2019’s X-Men: Dark Phoenix.

margaret ratliff the staircase
Netflix

…is playing Margaret Ratliff

Margaret is one of Michael Peterson’s adopted daughters. She featured heavily in Netflix’s docuseries The Staircase.

Patrick Schwarzenegger
Jason Kempin/Getty Images for CMA

Patrick Schwarzenegger

The actor who is also son of Arnold Schwarzenegger and Maria Shriver has appeared in shows such as Scream Queens and The Long Road Home. He’s best known for the film Midnight Sun in which he appeared alongside Bella Thorne. Schwarzenegger recently featured in the Netflix movie Moxie.

the staircase todd peterson
Netflix

…is playing Todd Peterson

Featured in Netflix’s docuseries of the same name, Todd Peterson is the son of Michael Peterson.

Michael Stuhlbarg - 2020 Sundance Film Festival - 'Shirley' Premiere
Neilson Barnard/Getty Images

Michael Stuhlbarg

Michael Stuhlbarg has made his mark on TV through roles on shows like Boardwalk Empire, Fargo, The Looming Tower, and most recently Your Honor. He’s also appeared in acclaimed films such as A Serious Man, Trumbo, The Shape of Water, The Post, and Call Me By Your Name.

David Rudolf
Netflix

…is playing David Rudolf

Rudolf was Peterson’s defense attorney who worked the case off and on for more than a decade. On his website, Rudolf provides an “inside view” of each episode of The Staircase and discusses the theory that an owl attack led to Kathleen’s death.