Kelley Mack, The Walking Dead Actress, Dies at 33 from Glioma
Actress Kelley Mack, best known as Addy on The Walking Dead, died at 33 from diffuse midline glioma after an eight-month battle. Her journey from a January 2025 diagnosis to her final days surrounded by family reveals not just a medical timeline, but a life of warmth and talent across television screens.
Born: July 10, 1992 ·
Died: August 2, 2025 ·
Age at death: 33 ·
Known for: Addy in The Walking Dead, roles on 9-1-1 ·
Cause of death: Glioma (brain cancer)
Quick snapshot
- Exact glioma subtype beyond diffuse midline glioma
- Date of initial diagnosis (public share was January 2025)
- Full scope of her Chicago Med role
- Exact date of first symptoms
- Specific grade of glioma
- Family continues to share tributes on Instagram and Facebook
- Legacy preserved on streaming platforms: The Walking Dead (Netflix/AMC+), 9-1-1 (Hulu/Disney+)
- Fan memorials and co-star remembrances expected
Seven key facts about Kelley Mack, from her full name to the cause that took her too soon.
| Label | Value |
|---|---|
| Full name | Kelley Lynne Klebenow |
| Born | July 10, 1992 |
| Died | August 2, 2025 |
| Age | 33 |
| Occupation | Actress, producer, voice over artist |
| Known for | Addy in The Walking Dead, 9-1-1, Chicago Med |
| Cause of death | Glioma |
What did Kelley Mack pass away from?
Kelley Mack died from a glioma — a type of brain tumor affecting the central nervous system — at the age of 33. Her family confirmed her passing on August 2, 2025, in a statement shared on social media. ABC News (a U.S. broadcast network) reported that Mack had revealed in January 2025 she had been diagnosed with diffuse midline glioma, an extremely rare type of astrocytoma cancer.
Mack’s case highlights how diffuse midline glioma can evade early detection — her initial symptoms of lower back and leg pain were easily mistaken for common musculoskeletal issues before an MRI on November 4, 2024, revealed the truth.
What kind of glioma did Kelley Mack have?
- Mack was diagnosed with diffuse midline glioma, according to NBC News (a major U.S. news outlet).
- Diffuse midline glioma is an aggressive brain tumor that grows in the midline structures (thalamus, brainstem, spinal cord). The specific grade or subtype has not been publicly disclosed beyond this broad classification.
- The diagnosis was noted in her obituary and social media posts, but the exact subtype within the glioma family remains unconfirmed.
When did Kelley Mack get diagnosed with glioma?
- An emergency MRI on November 4, 2024, revealed an abnormal mass on her spinal cord, per TODAY (a U.S. morning news program).
- Mack publicly shared her diagnosis in January 2025 on Instagram, describing persistent lower back pain and shooting pains in her legs and back that led to the discovery.
- By April 2025, she had completed proton radiation treatment, a targeted form of radiotherapy, according to NBC News.
- A secondary report from Times of India (an international news outlet) notes that she had shared a diagnosis of central nervous system glioma as early as September 2024, though this timeline is less certain.
The gap between early symptoms (lower back pain) and formal diagnosis underscores a challenge: diffuse midline glioma often presents with vague neurological signs that patients and even doctors may initially misattribute. For patients in the U.S. with persistent spine pain plus neurological symptoms, Mack’s story is a sobering reminder to push for imaging early.
Who is Kelley Mack in The Walking Dead?
Kelley Mack played Addy, a member of the Hilltop community, in season 9 of The Walking Dead. Her character was part of the sprawling survivor group living at the Hilltop settlement under leader Jesus (played by Tom Payne). NBC News identified her as best known for this role, which aired in 2018–2019 when Mack was 26 years old.
What happened to Addy on The Walking Dead?
- Addy was a loyal Hilltop resident who appeared primarily during the Whisperer conflict arc.
- Her character did not survive the series — she was among those killed during the encounter with the Whisperers, though specific episode details are part of the season 9 narrative.
A single role, but it connected her with millions of fans worldwide who now mourn her real-life loss far earlier than any script would have dictated.
How old was Kelley Mack when she played in The Walking Dead?
- Born July 10, 1992, Mack was 26 when she filmed season 9 (which aired in October 2018).
- She was 33 at the time of her death — a span of just seven years that contained her breakout television work and her final health battle.
The pattern: Mack’s Walk Dead role was her breakout, but seven years later the disease that took her had already started growing.
Who was Kelley Mack on 9-1-1?
Kelley Mack appeared in the TV series 9-1-1 as a guest character. TODAY notes that she was recognized for roles in both 9-1-1 and The Walking Dead, though the exact character name and episode details have not been widely documented in public sources. Her portfolio also included a role on Chicago Med, adding to a modest but meaningful television resume that spanned multiple major network series.
Fans searching for a complete filmography of Mack’s work will find limited publicly available records. Her Chicago Med role, in particular, lacks detailed character information in accessible databases — a gap that reflects how even talented actors early in their careers don’t always get comprehensive documentation until tragedy makes them a subject of broader interest.
The implication: Mack’s TV career left only sparse records outside her two best-known roles, a void that posthumous coverage now tries to fill.
What is the latest news on Kelley Mack?
Tributes continue to pour in following Kelley Mack’s death on August 2, 2025. Her family announced the news on Instagram and Facebook, stating she died peacefully surrounded by her mother Kristen and aunt Karen, per NBC News. ABC7 New York (a local U.S. news station) reported that her family cited the cause as glioma of the central nervous system. News outlets including ABC News, NBC News, and TODAY have all covered her passing, while social media platforms host an outpouring of fan and co-star condolences.
The pattern: a young actress’s death from a rare cancer sparks widespread media coverage, but the details of her life beyond those two cornerstone roles — Addy and the 9-1-1 guest spot — remain sparse, leaving a hole in the public record.
Timeline: Kelley Mack’s life and illness
- July 10, 1992: Kelley Lynne Klebenow born in Cincinnati, Ohio (Wikipedia).
- 2018–2019: Portrays Addy in The Walking Dead season 9 (NBC News).
- November 4, 2024: Emergency MRI reveals abnormal mass on spinal cord (TODAY).
- January 2025: Mack publicly shares diffuse midline glioma diagnosis via Instagram (ABC News).
- April 2025: Completes proton radiation treatment (NBC News).
- August 2, 2025: Dies at 33 in Cincinnati, Ohio, surrounded by family (ABC News).
What this means: Each milestone from diagnosis to proton therapy to death happened within 10 months, showing the aggressive course of diffuse midline glioma.
Confirmed facts vs. what remains unclear
Confirmed facts
- Full name: Kelley Lynne Klebenow (Wikipedia)
- Birth date: July 10, 1992 (Wikipedia)
- Death date: August 2, 2025 (ABC News)
- Cause of death: glioma (ABC7 New York)
- Role in The Walking Dead: Addy (season 9) (NBC News)
- Appearance on 9-1-1 (TODAY)
- Family announcement on Instagram and Facebook (NBC News)
What’s unclear
- Exact subtype of glioma beyond diffuse midline glioma
- Date of diagnosis (public share was January 2025; possible earlier)
- Role in Chicago Med (character details)
- Full list of acting credits
- Details of personal life (marriage, children)
- Exact date of first symptoms
- Specific grade of glioma
“It is with indelible sadness that we are announcing the passing of our dear Kelley.”
— Family of Kelley Mack, via Instagram
“Actress Kelley Mack, known for her appearance in The Walking Dead, has died at 33.”
— ABC7 New York
For fans of The Walking Dead and the broader television community, the loss of Kelley Mack is a reminder that behind every supporting role is a real person with a story that can end far too soon. The choice to honor her legacy is clear: watch her performance as Addy, share her story, and support research into rare gliomas that claim lives like hers before they reach their prime.
youtube.com, aol.com, walkingdeadbr.com, hindustantimes.com, alternativemindz.com, imdb.com
Her legacy includes a detailed account of her journey that highlights both her on-screen work and her real-life courage.
Frequently asked questions
What was Kelley Mack’s full name?
Kelley Lynne Klebenow.
How old was Kelley Mack when she died?
She was 33 years old.
What other TV shows did Kelley Mack appear in besides The Walking Dead and 9-1-1?
She also appeared in Chicago Med, though her specific character details are not widely documented.
Did Kelley Mack have any children?
Her family’s public statements did not mention children; no confirmed reports indicate she had any.
Where was Kelley Mack from?
She was born and died in Cincinnati, Ohio, USA.
What did Kelley Mack’s family say about her death?
They announced her passing on Instagram and Facebook, stating she died peacefully surrounded by her mother and aunt.
How did fans react to Kelley Mack’s passing?
Fans have shared tributes on social media, expressing grief and remembering her warmth and talent as Addy on The Walking Dead.
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