Just months before her tragic death at 33, The Walking Dead actress Kelley Mack was fighting a battle most couldn’t see and re-learning how to walk was just one piece of it. While fans knew her as Addy from AMC’s post-apocalyptic universe, those who followed Mack’s journey on Instagram saw a woman facing glioma, a rare brain tumor, with honesty, wit, and strength. “Legs are on fire,” she said in a video of herself attempting to walk down stairs with help from her boyfriend, Logan.

She didn’t hide the pain. She didn’t sugarcoat the process.

It’s crazy, I go to so many workout classes, and then you don’t walk for a month and it’s like, s*it, my legs are turning into twigs.

In another Instagram post, Mack detailed her healing timeline like a quiet soldier keeping score: radiation treatment finished, physical therapy ongoing, a warm-weather relocation to Florida, and foot massages paired with Monsters Inc. to ease the toll. “It’s a challenge that’s really good for me,” she admitted. “Improvements are tough to see when you’re in the thick of it.”

Sadly, on August 2, Mack passed away in Cincinnati, with her mother Kristen and aunt Karen by her side. Her sister Kathryn shared the heartbreaking announcement on August 5 via Mack’s Instagram.

Who Was Kelley Mack? Her Career, Legacy & Final Remembrance Service, Everything to Know

Kelley Mack | Credit: Instagram@itskelleymack
Born Kelley Lynne Klebenow in Cincinnati on July 10, 1992, Kelley Mack stepped into the spotlight early, acting in commercials as a child. Per THR, her passion matured at New York’s Tisch School of the Arts, where she received an acting award for The Elephant Garden, a film that went on to win at the Tribeca Film Festival.

Over the years, Mack brought grit and warmth to the screen in projects like The Walking Dead (as Addy in Season 9), Chicago Med, 9-1-1, and Schooled. Her indie credits included Broadcast Signal Intrusion opposite Harry Shum Jr., and the upcoming feature Universal, which she executive produced.

She also left her mark behind the camera: writing, directing, and editing short films, including Positive and A Knock at the Door, which earned awards at genre film festivals. In 2018, she voice-matched Gwen Stacy (originally voiced by Hailee Steinfeld) in Spider-Man: Into the Spider-Verse.

After completing proton radiation treatment in early 2025, Mack’s family kept her followers updated. They announced a remembrance on August 16 at the Glendale Lyceum in Ohio.

What Is a Glioma of the Central Nervous System?

Kelley Mack | Credit: Instagram@itskelleymack
Glioma of the central nervous system, the condition that claimed Kelley Mack’s life, is a rare tumor that originates in the glial cells of the brain or spinal cord. According to the National Cancer Institute, these tumors can be either malignant or benign, but even non-cancerous gliomas can cause significant neurological damage depending on their size and location. They are typically categorized by how fast they grow.

Mack’s case, while not publicly detailed in medical terms, was seemingly aggressive, evidenced by her need for proton radiation, physical therapy, and her documented struggles with basic mobility. The disease is reportedly difficult to treat and often progresses despite intervention.

Her openness about the physical and emotional burden of the illness gave her followers rare insight into a condition that is often misunderstood. Her posts became both journal and legacy, an archive of perseverance and vulnerability.

As we reflect on her final Instagram posts, her quiet humor, and the strength it took to re-learn how to walk while the world expected her to keep smiling, one question lingers: Will the industry finally start listening to voices like hers before they fall silent?

More to come as the legacy of Kelley Mack continues to unfold!