‘Walking Dead’ Star Kelley Mack Dies at 33 After Rare Brain Cancer Battle

Actress Kelley Mack, best known for portraying Addy in AMC’s The Walking Dead, has tragically passed away at the age of 33. Mack died peacefully on Saturday in her hometown of Cincinnati, Ohio, following a public and courageous battle with a rare form of brain cancer known as diffuse midline glioma.

The heartbreaking news was confirmed by her agent, Julie Smith, who revealed that Mack had been fighting the aggressive central nervous system cancer since her diagnosis became public earlier this year. Despite partial paralysis, the actress continued to share optimistic updates on her recovery journey through social media, inspiring fans and fellow actors alike.

Mack, whose birth name was Kelley Klebenow, was surrounded by close family members at the time of her passing. Her sister shared the news on Instagram, stating, “Kelley passed peacefully on Saturday evening with her loving mother Kristen and steadfast aunt Karen present.”

What happened to Kelley Mack?

Kelley Mack, known to fans for her breakout role in The Walking Dead Season 9, was diagnosed with diffuse midline glioma—an exceptionally rare and aggressive brain tumor that primarily affects the brainstem and spinal cord. The disease rapidly impacted her motor functions, leading to partial paralysis. However, Mack remained hopeful and shared personal milestones throughout her treatment, including a touching video of her climbing stairs in March.

Her diagnosis came to light in January 2025, and she quickly became a voice of resilience, gaining admiration across the entertainment industry and beyond. Her openness about her health challenges offered comfort and solidarity to many fighting similar battles.

Remembering Kelley Mack: A Rising Talent Silenced Too Soon

Beyond The Walking Dead, Kelley Mack made notable appearances on Chicago Med and starred in several independent films, including Mr. Manhattan, Broadcast Signal Intrusion, and Delicate Arch. Her performances were consistently praised for their depth, vulnerability, and emotional authenticity.

Co-stars from The Walking Dead paid tribute following her passing, with several remembering her as a “bright light” both on and off screen. Director Michael E. Satrazemis expressed deep sorrow, stating Mack was “a bright light on every level.”

Her work ethic, artistic dedication, and warm personality left an indelible mark on everyone she worked with, especially in an industry where authentic kindness is rare and deeply cherished.

Why It Matters: Highlighting a Rare Brain Tumor

Diffuse midline glioma, the illness Mack succumbed to, is among the most challenging and under-researched forms of cancer. Its rarity and aggressiveness make early diagnosis and treatment particularly difficult. Advocacy groups and medical researchers have called for more awareness and funding to combat this devastating disease.

According to global health experts, raising awareness about such cancers is essential not only for medical advancements but also to provide emotional support systems for those diagnosed. Mack’s openness about her journey has inadvertently become a catalyst for broader conversations on rare brain diseases.

What’s Next: Honoring Her Legacy

A public remembrance service for Kelley Mack will be held on August 16 in Ohio. Fans, friends, and colleagues are expected to attend, celebrating her life, talent, and the courage with which she faced her diagnosis.

Her family has not disclosed details about a memorial fund, but many in the entertainment community are calling for donations to brain cancer research initiatives in her honor.

Kelley Mack’s legacy lives on not only through her memorable performances but through the lives she touched by sharing her deeply human experience with rare brain cancer.

You Must Know:

What did Kelley Mack die of?
Kelley Mack passed away due to diffuse midline glioma, a rare and aggressive brain tumor that affects the central nervous system.

What was Kelley Mack’s most famous role?
She is best known for her portrayal of Addy in Season 9 of AMC’s The Walking Dead.

When did Kelley Mack die?
Kelley Mack passed away on Saturday, August 2, 2025, in her hometown of Cincinnati, Ohio.

Was Kelley Mack public about her illness?
Yes, she publicly revealed her diagnosis in January 2025 and often shared updates about her treatment and recovery on social media.

How old was Kelley Mack when she died?
She was 33 years old.

Is there a public memorial for Kelley Mack?
Yes, a remembrance service will be held on August 16 in Ohio.