The Staircase: Who's Who in HBO Max's Michael Peterson Docudrama

From The Dropout to Winning Time, docudramas have been dominating prestige TV, and this week HBO Max gets in on the action with The Staircase, a dramatic retelling of the Michael Peterson case. In 2003 Peterson was convicted of kiling his wife Kathleen, who was found dead two years earlier at the bottom of the stairs in their home. Petersen's trial and the fifteen years of appeals that folowed were previously the subject of a 13 part docuseries (also titled The Staircase), but HBO Max is now putting its own spin on Petersen's story with a star-studded limited series. Who were the major players in the case, and who’s stepping into their shoes in HBO Max's The Staircase? You've come to the right place:

Colin Firth as Michael Peterson

A Vietnam War veteran and North Carolina-based novelist, Michael Peterson was charged with murdering his second wife, Kathleen Peterson, on December 9, 2001. Peterson pleaded not guilty, but after a lengthy, high-profile trial, he was convicted of beating his wife to death and sentenced to life in prison without the possibility of parole. Peterson’s attorneys continued to appeal the verdict, and he was ultimately granted a new trial, but in 2017 he submitted an Alford plea — under which a defendant can maintain their innocence while acknowledging prosecutors have enough evidence for a conviction — to the reduced charge of manslaughter, bringing the decade-and-a-half legal ordeal to an end.

Shortly after Peterson’s arrest, a French film crew began documenting the case from Peterson’s perspective for a docuseries. The first iteration of the series, released in 2004, introduced Peterson’s case to the world at large, while Netflix’s three-episode 2018 follow-up followed his lengthy appeal process and eventual release.

Michael Peterson is played by Colin Firth, who ditches his British accent for the role. The award-winning actor is best known for his roles in prominent romances, including the 1995 TV adaptation of Pride and Prejudice, Bridget Jones’s Diary, and Shakespeare in Love, as well as acclaimed dramas like The King’s Speech (for which he won the Best Actor Oscar) and Sam Mendes’ 1917. Musical lovers will also recognize Firth as Mamma Mia!’s Harry Bright, one of Amanda Seyfried’s three possible fathers.

Toni Collette as Kathleen Peterson

Kathleen Peterson (formerly Atwater) was a successful Nortel business executive who married Michael in 1997. Four years later, on December 9, 2001, Peterson called the police after finding Kathleen unconscious at the bottom of a staircase inside their home. Peterson and his legal team argued that Kathleen must have fallen down the stairs after consuming alcohol and Valium, but an autopsy concluded that the 48-year-old woman sustained head injuries consistent with blows from a blunt object. Despite Peterson’s eventual Alford plea, questions remain surrounding Kathleen’s death, and new theories, including "the Owl Theory," remain under investigation.

In The Staircase, Kathleen Peterson is played by Toni Collette. Colette first broke into Hollywood in the 1990s with Muriel’s Wedding and The Sixth Sense, and she's continued to wow audiences with her strong and varied performances in the decades since. The actor splits her time between film and television projects, having recently appeared in Ari Aster’s Hereditary, murder mystery Knives Out, BBC drama series Wanderlust, and the Netflix docudrama Unbelievable, for which she earned an Emmy nomination.

Sophie Turner as Margaret Ratliff

Sophie Turner plays Margaret Ratliff, the eldest daughter of Elizabeth and George Ratliff. In the 1970s and ‘80s, Peterson and his first wife Patricia lived in Germany, and they became close friends with the Ratliffs and their two children, Margaret and Martha. Sadly, both George and Elizabeth died — Elizabeth, too, was found at the foot of her staircase with injuries to her head in 1985 — and Michael became Margaret and Martha’s guardian, eventually moving them back to Durham, North Carolina with the rest of his family.

Turner is best known for playing Sansa Stark in HBO’s Game of Thrones, but she’s also made a name for herself as a young Jean Grey/Phoenix in the X-Men movies and as the lead of Quibi thriller Survive.

Odessa Young as Martha Ratliff

Odessa Young, who plays youngest Ratliff daughter Martha, is no stranger to prestige dramas. The Australian actor broke out in Simon Stone’s 2015 film The Daughter before landing roles in Assassination Nation, A Million Little Pieces, and The Stand limited series adaptation. Young can next be seen in John Trengove’s English-language debut Manodrome, which also stars Jesse Eisenberg, Adrien Brody, and Riley Keough.

Dane DeHaan as Clayton Peterson

Clayton Peterson, one of two sons from Peterson’s first marriage to Patricia Sue, is played by Dane DeHaan. Viewers will recognize him as Harry Osborn/Green Goblin in 2014 film The Amazing Spider-Man 2 and as Billy the Kid in Vincent D’Onofrio’s The Kid, in which he starred opposite Ethan Hawke. DeHaan has also appeared in Prime Video’s ZeroZeroZero and Apple TV+ miniseries Lisey’s Story.

Patrick Schwarzenegger as Todd Peterson

Patrick Schwarzenegger stars opposite DeHaan as Todd Peterson, the other son from Peterson’s marriage to Patricia Sue. Schwarzenegger is intimately familiar with being part of a large, famous family: he’s the son of Arnold Schwarzenegger and Maria Shriver. The 28-year-old has been acting since he was a child, but his first leading role came in 2018 romance Midnight Sun, followed by horror thriller Daniel Isn’t Real. In the years since, he's appeared in Amy Poehler’s Moxie and science fiction thriller Warning.

Olivia DeJonge as Caitlin Atwater

Kathleen’s daughter from a previous relationship, Caitlin Atwater initially supported Peterson, maintaining his innocence alongside his other children. Caitlin reconsidered after reading her mother’s autopsy report, and later broke off from the rest of the family. In October 2002, acting as administrator of Kathleen’s estate, she filed a wrongful death claim against Peterson; five years later, the two settled for $25 million.

Caitlin plays a large role in The Staircase, and producers have selected up-and-comer Olivia DeJonge to tell her story. The Australian actor is best known for performances in M. Night Shyamalan’s The Visit and Netflix teen drama The Society, but she’s set to break out in a major way as Priscilla Presley in Baz Luhrmann’s upcoming Elvis Presley biopic.

Parker Posey as Freda Black

Durham County assistant district attorney Freda Black led the prosecution in the Peterson trial, one of the longest in North Carolina history. Black and her colleagues contended that Peterson had a “gay life” that he kept hidden from his family, and she suggested that he killed Kathleen when she discovered his secret and threatened to end their marriage.

Black is portrayed in the new limited series by Parker Posey, who has captivated audiences for decades with performances in Waiting for Guffman, Best in Show, and You’ve Got Mail. Posey has also guest starred in countless television series, from Parks and Recreation to The Good Wife, and joins The Staircase after three seasons at the helm of Netflix drama Lost in Space.

Michael Stuhlbarg as David Rudolf

Defense attorney David Rudolf spent over a decade representing Peterson, becoming something of an advisor to the family along the way. During the 2003 trial, Rudolf refuted Black’s argument, contending that Kathleen accepted Peterson’s bisexuality and that their marriage was happy at the time of her death. After the verdict was handed down, Rudolf continued to support Peterson throughout the appeals process, working pro bono on the case after Peterson filed for bankruptcy.

Squaring off against Posey’s Freda Black is Michael Stuhlbarg. Beyond his acclaimed film work — he appeared in three Best Picture nominees in 2017: Call Me By Your Name, The Shape of Water, and The Post — Stuhlbarg has portrayed a host of real-life characters on television, including Arnold Rothstein in HBO’s Boardwalk Empire, national security expert Richard A. Clarke in The Looming Tower, and Richard Sackler in Dopesick.

Rosemarie DeWitt as Candace Hunt Zamperini

Like Caitlin Atwater, Kathleen's sister Candace Hunt Zamperini initially proclaimed Peterson’s innocence, before changing tack after learning of his bisexuality.

As the family member most willing to speak out against Peterson, Zamperini was a prominent figure in The Staircase docuseries, and she plays an equally important role in this dramatization. Zamperini is played by Rosemarie DeWitt, who reunites with her United States of Tara co-star Toni Collette. DeWitt was also the title character in acclaimed drama Rachel Getting Married, and starred in 2015 horror thriller Poltergeist and Hulu’s Little Fires Everywhere adaptation.

Juliette Binoche as Sophie Brunet

In 2018, Sophie Brunet, an editor on Netflix’s The Staircase, made headlines when director Jean-Xavier de Lestrade revealed that Brunet and Peterson were romantically involved while working on the docuseries. Peterson said that he and Brunet became close while he was in prison, but after living together briefly in France, they broke up.

Who better to play the French editor than Juliette Binoche? After coming up in French cinema, Binoche became a global sensation thanks to her performance in The Unbearable Lightness of Being, and over the next two decades she appeared in countless acclaimed films and stage productions, including The English Patient (for which she won the Academy Award for Best Actress), and Chocolat, earning her another Oscar nomination. The Staircase marks Binoche’s first major television role, though she has appeared in four TV movies and played herself in a 2017 episode of Call My Agent!.

The Staircase premieres May 5th on HBO Max. New episodes drop Thursdays through June 9th.

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Claire Spellberg Lustig is the Senior Editor at Primetimer and a scholar of The View. Follow her on Twitter at @c_spellberg.