I Know What You Did Last Summer (TV) Cast
The cast of I Know What You Did Last Summer. Updated on September 17, 2025.
41 actors
Madison Iseman
as Lennon / Alison (8 episodes)

Madison Iseman stars as Lennon / Alison, one of the main characters in I Know What You Did Last Summer. Lennon is a young woman haunted by a dark secret from her past. As the story unfolds, she finds herself caught up in a series of terrifying events.

Bill Heck
as Bruce (8 episodes)

Bill Heck portrays the character of Bruce in I Know What You Did Last Summer. Bruce is a charismatic and confident member of the group of friends who share a deadly secret. As the mystery unravels, Bruce's loyalty and strength are put to the test.

Brianne Tju
as Margot (8 episodes)

Brianne Tju takes on the role of Margot in I Know What You Did Last Summer. Margot is a bright and ambitious young woman with a troubled past. As the secrets of her friends come to light, Margot must confront her own demons and make difficult choices.

Ezekiel Goodman
as Dylan (8 episodes)

Ezekiel Goodman plays the character of Dylan in I Know What You Did Last Summer. Dylan is a loyal friend who becomes entangled in the dangerous events that unfold in the aftermath of a tragic accident. As tensions rise, Dylan's courage and resourcefulness are put to the test.

Ashley Moore
as Riley (8 episodes)

Ashley Moore portrays the character of Riley in I Know What You Did Last Summer. Riley is a smart and resilient young woman who finds herself facing the consequences of the group's actions. As the horror intensifies, Riley must rely on her wit and strength to survive.

Fiona Rene
as Lyla (8 episodes)

Fiona Rene stars as Lyla in I Know What You Did Last Summer. Lyla is a compassionate and determined individual who becomes entangled in a web of secrets and lies. As the truth unravels, Lyla's loyalty and bravery are put to the ultimate test.

Cassie Beck
as Courtney (8 episodes)

Cassie Beck takes on the role of Courtney in I Know What You Did Last Summer. Courtney is a mysterious and enigmatic character who holds secrets of her own. As the story unfolds, Courtney's true motivations are revealed, leading to shocking revelations.

Brooke Bloom
as Clara (8 episodes)

Brooke Bloom portrays the character of Clara in I Know What You Did Last Summer. Clara is a complex and intriguing individual who becomes involved in the dangerous events surrounding the group's dark secret. As the tension rises, Clara must navigate the treacherous waters of trust and betrayal.

Spencer Sutherland
as Dale (4 episodes)
Eddie Kaulukukui
as Carl Gilbert (2 episodes)
Tiffany Kanoa
as Kid (1 episode)
Kekoa Kekumano
as Connor Davenport (2 episodes)
Keola Simpson
as Mr. Davenport (2 episodes)
Sebastian Amoruso
as Johnny (2 episodes)
Danielle Delaunay
as Hannah Scanlon (5 episodes)
Chrissie Fit
as Kelly Craft (4 episodes)
Victoria K. Schmidt
as Officer Ulani Kalama (4 episodes)
Jason Lee Hoy
as Kyle (4 episodes)
Sterling Sulieman
as Wade (3 episodes)
Eric William Morris
as Officer Doug Cruise (2 episodes)
Maggie Lacey
as Helen (1 episode)
Joe Toro
as Bill (1 episode)
Duncan Kamakana
as Eric Craft (1 episode)
Dann Seki
as Harold (2 episodes)
Lori Pelenise Tuisano
as Customer (1 episode)
Saint Thompson
as Officer (1 episode)
Linda Castro
as Protestor # (1 episode)
Claire Unabia
as Well-Wisher (1 episode)
Kamri Lin
as Mourner #1 (1 episode)
Steven Se Kyung Sung
as Mourner #2 (1 episode)
Jimmy Atimua
as Townsperson (1 episode)
Loretta Ables Sayre
as Jean Kalai (2 episodes)
Taylor Kowalski
as Selfie Guy (1 episode)
Shane Miyashiro
as Desk Officer (2 episodes)
Kolton Tokuoka
as Kai Craft (1 episode)
Ticondra Swartz
as Surgeon (1 episode)
Olivia Frye
as Little Kid (1 episode)
Likkle Jordee
as On Camera Singer (1 episode)
Christina Souza
as Wainani (1 episode)
Trevor Danielson
as Paramedic (1 episode)
Dann Seki
as Harold (2 episodes)
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