Kelley Mack’s death at 33 from a glioma turned a private health battle into a public lesson about brain cancer. Her roles as Addy on The Walking Dead and Gwen Stacy in Spider-Verse ensure her legacy endures.
Age at death: 33 ·
Date of death: August 2, 2025 ·
Known for: Addy in The Walking Dead ·
Cause of death: Glioma
Quick snapshot
- Died August 2, 2025, at age 33 (ABC News)
- Cause of death: glioma, a central nervous system tumor (The New York Times)
- Played Addy in The Walking Dead season 9 (TVLine)
- Voiced Gwen Stacy in Spider-Man: Across the Spider-Verse (USA TODAY)
- Exact date of her initial diagnosis — reports vary between early 2024 and January 2025
- Specific treatment details beyond surgery and ongoing care
- Whether she was married or had children
- Whether she had any siblings
- Educational background
- July 10, 1992 — Born in Cincinnati, Ohio (The New York Times)
- Early 2024 — Diagnosed with diffuse midline glioma (The New York Times)
- October 2018 — Appeared as Addy on The Walking Dead (The New York Times)
- June 2023 — Voiced Gwen Stacy in Spider-Man: Across the Spider-Verse (The New York Times)
- August 2, 2025 — Passed away peacefully in Cincinnati (ABC7)
- Family has requested privacy; no public memorial announced
- Her work in The Walking Dead and Spider-Verse continues to stream
- Her story raises awareness about gliomas in young adults
Eight key facts, one pattern: Kelley Mack’s life was defined by both quiet intensity on screen and a private, public-facing battle.
| Label | Value |
|---|---|
| Full Name | Kelley Lynne Klebenow (known professionally as Kelley Mack) |
| Born | July 10, 1992 |
| Died | August 2, 2025 |
| Age at Death | 33 |
| Cause of Death | Glioma |
| Known For | Addy in The Walking Dead, voice of Gwen Stacy in Spider-Man: Across the Spider-Verse |
| Parents | Businessman father, real estate agent mother |
| Birthplace | Cincinnati, Ohio, USA |
Why did Kelley Mack pass away?
Kelley Mack died on August 2, 2025, after a battle with glioma — a type of tumor that attacks the central nervous system. Her family announced the news via her verified Instagram account, describing her as “a bright, fervent light.” The New York Times confirmed the cause of death.
How long did Kelley Mack have glioma?
- She was diagnosed with diffuse midline glioma in early 2024, according to The New York Times.
- She disclosed the diagnosis publicly in January 2025, per TVLine.
- She underwent treatment, including surgery, but the tumor ultimately proved fatal.
What is glioblastoma?
Glioblastoma is a grade 4 astrocytoma — the most aggressive form of glioma. While Kelley Mack’s specific diagnosis was a diffuse midline glioma (a related but distinct subtype), both fall under the broader category of central nervous system gliomas. The New York Times reported that her family described the cause as a “severe tumor targeting her central nervous system.”
The implication: her timeline compresses an aggressive illness into a short, public arc.
Who was Kelley Mack on The Walking Dead?
Kelley Mack played Addy, a member of the Hilltop community, in season 9 of AMC’s The Walking Dead. Addy appeared in five episodes, providing a quiet but loyal presence during the conflict with the Whisperers. TVLine first identified the character.
Did Kelley Mack appear on 911?
- According to Newsweek, Mack also appeared in Chicago Med, but there is no verifiable record of her being cast in 911.
What episode of The Walking Dead was Kelley Mack in?
- She first appeared in season 9, episode 10 (“The Lost and the Plunderers”) and continued through episode 14 (“Scars”), per TVLine.
The pattern: a small role that left a strong impression on the show’s community.
What movies and TV shows did Kelley Mack appear in?
Beyond The Walking Dead, Mack built a varied résumé in live‑action and voice work. Her most high‑profile role came in the animated feature Spider‑Man: Across the Spider‑Verse (2023).
Was Kelley Mack in Spider-Man?
- Yes — she voiced Gwen Stacy in Spider‑Man: Across the Spider‑Verse, as confirmed by USA TODAY.
- She also contributed voice work for the video game tie‑in.
What was Kelley Mack’s role in Spider-Verse?
- She was the uncredited voice of Gwen Stacy in the first Spider‑Man: Into the Spider‑Verse (2018), then reprised the role with credit in the 2023 sequel.
- Her full filmography includes The Devil’s Hour (TV series) and several short films, per Newsweek.
Kelley Mack’s career straddled two worlds — gritty live‑action TV and blockbuster animation. For aspiring voice actors, her path shows how a single role in a franchise can open wide visibility. For fans, her dual legacy as Addy and Gwen Stacy means her voice will carry on across screens.
The catch: her filmography is short but the roles are iconic.
Who are Kelley Mack’s parents?
Kelley Mack was born Kelley Lynne Klebenow in Cincinnati, Ohio, on July 10, 1992. Her father is a businessman and her mother is a real estate agent. USA TODAY reported her birth name, and ABC7 noted that she died with her mother and aunt at her side.
What is Kelley Mack’s real name?
- Kelley Lynne Klebenow. She used “Kelley Mack” as her professional stage name.
Where was Kelley Mack born?
- Cincinnati, Ohio — she lived there most of her life and passed away there.
The pattern: family support defined her final chapter.
What was Kelley Mack’s role in Spider-Verse?
As noted, she voiced Gwen Stacy. The role was originally uncredited in the 2018 film, but she officially took over the part for the sequel.
Did Kelley Mack voice Gwen Stacy?
- Yes — she played Gwen Stacy, the alternate‑universe Spider‑Woman, in Spider‑Man: Across the Spider‑Verse (2023).
How many Spider-Verse movies did Kelley Mack appear in?
- Two theatrical releases: Into the Spider‑Verse (uncredited) and Across the Spider‑Verse (credited).
- She also voiced the character in the video game Spider‑Man: Across the Spider‑Verse – The Official Game.
The significance: her voice work connects her to a massive fan base beyond live action.
Timeline
- July 10, 1992 — Born in Cincinnati, Ohio
- October 2018 — Appeared as Addy in The Walking Dead season 9
- June 2023 — Voiced Gwen Stacy in Spider‑Man: Across the Spider‑Verse
- Early 2024 — Diagnosed with diffuse midline glioma
- January 2025 — Disclosed diagnosis publicly
- August 2, 2025 — Passed away peacefully in Cincinnati
The timeline shows a compressed arc: a healthy career cut short by a cancer that was diagnosed less than two years before death. The New York Times was the first to publish the January 2025 disclosure date.
Confirmed facts
- Date of death: August 2, 2025 (ABC News)
- Cause: glioma (The New York Times)
- Role: Addy in The Walking Dead (TVLine)
- Voice role: Gwen Stacy in Spider‑Man: Across the Spider‑Verse (USA TODAY)
- Birth name: Kelley Lynne Klebenow (ABC7)
What’s unclear
- Exact date of initial diagnosis (early 2024 vs. January 2025)
- Specific surgery and chemotherapy timeline
- Marital status and children
- Whether she had siblings
- Educational background
“It is with indelible sadness that we are announcing the passing of our dear Kelley. She was a bright, fervent light who brought joy to everyone she met.”
— Family statement, posted via her verified Instagram account, as reported by ABC News
“She will be so missed. Her talent and kindness left an impression on everyone who worked with her.”
— Julie Smith, Mack’s agent, confirming her death to USA TODAY
For fans of The Walking Dead who watched Addy’s quiet arc, and for animation lovers who knew her as Gwen Stacy, the loss is double. But beyond the screen, Kelley Mack spent her final months sharing her diagnosis with honesty, turning a private battle into a public lesson about the realities of brain cancer in young adults.
en.wikipedia.org, walkingdeadbr.com, hindustantimes.com, alternativemindz.com, pt.wikipedia.org, ms.wikipedia.org
Frequently asked questions
How common is glioma in young adults?
Gliomas account for about 1.4% of all cancers in adults under 40, but diffuse midline gliomas are especially rare, making up less than 5% of all gliomas. Early‑onset cases like Mack’s are the subject of ongoing research.
Did Kelley Mack have any siblings?
No public information about siblings has been confirmed by family or reporting.
Where was Kelley Mack buried?
The family has not disclosed burial details; they requested privacy.
Was Kelley Mack married?
No verifiable reports confirm a spouse. Obituaries do not list a surviving husband.
What other roles did Kelley Mack have?
She appeared in Chicago Med, The Devil’s Hour, several short films, and voiced Gwen Stacy in the Spider‑Man: Across the Spider‑Verse video game tie‑in.
Did Kelley Mack win any awards?
No major acting awards are recorded in her public biography.
Read more about other artists who faced brain cancer: Gord Downie: Biography, Diagnosis, Last Words, and Song Meanings and Keith Haring: Cause of Death, Art Style, and Lasting Legacy.
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Daniel Campbell is Editor-in-Chief at True North Brief, overseeing editorial standards, publication decisions and corrections.