The Staircase Cast

Colin Firth portrays the lead character, Michael Peterson. Michael is a novelist and former mayoral candidate who finds himself at the center of a murder investigation when his wife is found dead at the bottom of the staircase.

Toni Collette plays Kathleen Peterson, Michael's wife. Kathleen is a successful business executive, and her tragic death sets off a chain of events that form the basis of the show's gripping story.

Michael Stuhlbarg portrays David Rudolf, Michael Peterson's defense attorney. David is a skilled and dedicated lawyer, determined to prove his client's innocence amidst a web of evidence and suspicion.

Dane DeHaan plays Clayton Peterson, Michael's son from a previous marriage. Clayton struggles with the accusations against his father and grapples with the impact it has on his own life and relationships.

Olivia DeJonge portrays Caitlin Atwater, a journalist assigned to cover the case. Caitlin becomes immersed in the Peterson family's story and uncovers new information that could change the course of the trial.

Patrick Schwarzenegger plays Todd Peterson, Michael's biological son. Todd supports his father throughout the trial and stands by him, despite the mounting evidence against him.

Sophie Turner portrays Margaret Ratliff, Michael Peterson's adopted daughter. Margaret becomes a key figure in the investigation and provides crucial insight into her family dynamics.

Odessa Young plays Martha Ratliff, Margaret's biological sister and Michael Peterson's other adopted daughter. Martha's perspective and possible involvement in the case add further complexity to the story.