Kelley Mack, known to many as Addy on The Walking Dead, died on August 2, 2025, at just 33 years old. Her cause of death was diagnosed as a central nervous system glioma, a rare and aggressive tumor. Public searches for terms like kelley mack walking dead, glioma, kelley mack death, and kelley mack cause of death have surged as fans and media around the world remember her talent and courage.
From The Walking Dead to Chicago Med and Beyond
Born Kelley Lynne Klebenow in Cincinnati, Mack built a diverse acting career spanning television, film, and voice work. She appeared as Addy in season 9 of The Walking Dead, and had guest roles on Chicago Med and 9-1-1. Fans searching kelley mack chicago med or addy the walking dead quickly found her empathetic performances and grounded realism. Mack also voice-match performed Gwen Stacy in Spider-Man: Into the Spider-Verse promotions.
Central Nervous System Glioma: The Rare Diagnosis
Her family revealed that Mack was diagnosed with diffuse midline glioma, a type of central nervous system glioma known for its poor prognosis and limited treatment options. This cancer forms in glial cells within critical brain regions such as the brainstem or spinal cord, making surgical removal nearly impossible. Mack faced rapid disease progression, and underwent aggressive treatment including spinal biopsy—which ultimately impacted her mobility. Despite using a walker and wheelchair, she documented physical progress with grace and gratitude. 
A Legacy Beyond the Diagnosis
Her Instagram and CaringBridge statements, shared by her sister and family, emphasized her bravery: “Such a bright, fervent light has transitioned… Kelley has already come to many of her loved ones in the form of various butterflies.” Her final film, Universal, was filmed and released in 2025, weeks before her death. She had also appeared in Broadcast Signal Intrusion, Delicate Arch, and Mr. Manhattan, showcasing her dedication to storytelling across genres.
What Fans Are Searching: Kelley Mack News and Legacy
Search traffic soared for kelley mack news, kelly mack death, and kelley mack walking dead. Fans remembered her role as Addy, while others sought updates via kelley mack 911 and kelley mack chicago med. The rapid spread of reports through media sources like Hollywood Reporter, People, Entertainment Weekly, and others cemented her memory in entertainment circles. Her passing also raised conversations about glioma awareness and support for rare brain cancer research.
Frequently Asked Questions
What was Kelley Mack’s cause of death?
She passed away from a central nervous system glioma—a particularly aggressive form of brain tumor with limited treatment options.
How old was she?
Mack was 33 when she died on August 2, 2025, in Cincinnati, surrounded by her family.
What roles is she known for?
She portrayed Addy in The Walking Dead (Season 9), had guest roles on Chicago Med and 9-1-1, and appeared in films like Broadcast Signal Intrusion and Universal.
Does she have upcoming releases?
Her role in Universal was her final project, released shortly before her death. A remembrance event is scheduled for August 16 in her hometown.
Is glioma treatable?
Diffuse midline glioma has a poor prognosis; treatments are limited and primarily palliative. Mack’s battle highlighted the emotional toll and medical challenges of the diagnosis.
Kelley Mack’s death leaves an indelible mark on fans and colleagues who admired her warmth, creativity, and storytelling impact. Her courage in facing such a devastating illness, while continuing to create art, inspires more recognition for rare cancers like glioma. As her memory endures through her roles and final words of hope, many are left reflecting on both what she accomplished—and how much more she might have shared.
Subscribe to stay updated on entertainment tributes, medical advocacy, and film retrospectives.
