Patrick Wilson plays Josh Lambert in Insidious (2011), the father who moves his family into a new house shortly before his son Dalton falls into a coma that doctors cannot explain. James Wan told Dread Central that Wilson and Rose Byrne were the two people he wanted immediately, and that getting both top choices never happens. Wilson later directed Insidious: The Red Door (2023) and played Josh again in it.
Rose Byrne plays Renai Lambert in Insidious (2011), the mother who is at home with the children when strange noises and sightings begin to unsettle the family. Producer Oren Peli told The Film Stage that James Wan already had Byrne and Patrick Wilson in mind, that the team approached them, and that both responded well to the script. TMDB credits Byrne as Renai again in Insidious: Chapter 2 (2013) and Insidious: The Red Door (2023).
Lin Shaye plays Elise Rainier in Insidious (2011), the paranormal expert the family turns to as events in the house escalate. In a Dread Central interview, James Wan called her performance amazing and compared her to Zelda Rubenstein in Poltergeist. TMDB credits Shaye as Elise again in Insidious: Chapter 2 (2013) and in Insidious: The Red Door (2023).
Ty Simpkins plays Dalton Lambert in Insidious (2011), the boy who falls from a ladder in the attic and cannot be woken the next day. TMDB gives his birth date as August 6, 2001, so he was eight during the spring 2010 shoot. James Wan told Dread Central that Simpkins was terrified of the demon character, and that his crying on screen was real.
Barbara Hershey plays Lorraine Lambert in Insidious (2011), the mother of Josh who stands by the family as the trouble in the house grows. James Wan told Dread Central that Hershey, Rose Byrne and Patrick Wilson all came highly recommended. Hershey returns as Lorraine in Insidious: Chapter 2 (2013), where TMDB also credits Jocelin Donahue as Lorraine Lambert (adult). Hershey is not listed in the TMDB cast of Insidious: The Red Door (2023).
Leigh Whannell plays Specs, one of two ghost hunters in Insidious (2011), and he also wrote the screenplay. Whannell told Dread Central that working alongside the main cast was a little intimidating, but that it made him want to do better. He returns as Specs in Insidious: Chapter 2 (2013) and Insidious: The Red Door (2023), and he directed Insidious: Chapter 3 (2015) himself.
Angus Sampson plays Tucker, who makes up the ghost hunting duo with Specs in Insidious (2011). Leigh Whannell told Dread Central that Sampson is one of his best friends, and according to The Film Stage the two later worked together on The Mule, which Whannell co-wrote. TMDB credits Sampson as Tucker again in Insidious: Chapter 2 (2013) and in Insidious: The Red Door (2023).
Andrew Astor plays Foster Lambert in Insidious (2011), the brother of Dalton and one of the three Lambert children in the new house. TMDB lists him as Foster in Insidious: Chapter 2 (2013) and again in Insidious: The Red Door (2023). In that film he is billed fifth, behind Ty Simpkins, Patrick Wilson, Sinclair Daniel and Hiam Abbass.
Corbett Tuck as Nurse Adele / Doll Girl #2
Corbett Tuck is credited with two parts in Insidious (2011), Nurse Adele and Doll Girl #2, which makes her the only performer in the TMDB cast list with a double credit. The Doll Girl credit pairs her with Kelly Devoto, who is credited as Doll Girl #1. Dread Central reported that the filmmakers said on stage at the premiere that the film took only 22 days to shoot.
Heather Tocquigny as Nurse Kelly
Heather Tocquigny plays Nurse Kelly in Insidious (2011), one of two nurse credits in the TMDB cast list. The setup of the film moves from the new house to the hospital, where Dalton is declared to be in a coma with no medical cause. Her scenes come from a short production, since principal photography ran about three weeks, from late April to mid May 2010, at the Herald Examiner Building in downtown Los Angeles.
Ruben Pla as Dr. Sercarz
Ruben Pla plays Dr. Sercarz in Insidious (2011), the doctor credit in a story where the medical team can find no cause for the coma that Dalton falls into. Pla's work reached its first audience on September 14, 2010, when the film premiered in the Midnight Madness program at the Toronto International Film Festival.
John Henry Binder as Father Martin
John Henry Binder is credited as Father Martin in Insidious (2011), twelfth in the TMDB billing order. TheWrap reported that Sony Pictures Worldwide Acquisitions bought North American rights to the film in a seven figure deal after the Toronto premiere. FilmDistrict later handled the theatrical release, so his role reached US screens on April 1, 2011.