Who was Kelley Mack? ‘The Walking Dead’ actress who passed away at 33 following battle with glioma

Kelley Mack, best known for her role as Addy in the hit television series ‘The Walking Dead’, has died aged 33 after a courageous battle with a rare and aggressive form of brain cancer known as diffuse midline glioma.

The news of her passing was confirmed through a touching social media tribute posted by her sister on 5 August, revealing that Mack had died peacefully on August 2 in her hometown of Cincinnati, Ohio. She was surrounded by close family members, including her mother and aunt.

“It is with indelible sadness that we are announcing the passing of our dear Kelley. Such a bright, fervent light has transitioned to the beyond, where we all eventually must go,” the post read.

It continued: “Kelley passed peacefully on Saturday evening with her loving mother Kristen and steadfast aunt Karen present. Kelley has already come to many of her loved ones in the form of various butterflies. She will be missed by so many to depths that words cannot express.”

Mack is survived by her parents Kristen and Lindsay Klebenow; her sister, Kathryn; her brother, Parker; her grandparents, Lois and Larry Klebenow; and her boyfriend, Logan Lanier.

Kelley’s acting career

Born in 1992 in Cincinnati, Kelley Mack (birth name Kelley Lynne Klebenow) had been immersed in the world of entertainment since childhood. Her early start in commercials and advertisements paved the way for a career that would span multiple genres and platforms. Her official debut came in 2008 with ‘The Elephant Garden’, a performance that earned her an Acting Award from the Tisch School of the Arts and the Student Visionary Award at the Tribeca Film Festival.

Mack’s portfolio extended across television, film, streaming platforms, and even voice-over work. In addition to her breakout role in ‘The Walking Dead’ — where she played Addy in five episodes of season 9 — she also appeared in ‘Chicago Med’, ‘911’, and voiced Gwen Stacy in the critically acclaimed animated film ‘Spider-Man: Into the Spider-Verse’.

She also left her mark behind the camera. A passionate filmmaker, Mack studied film production and cinematography and went on to create the short film ‘Positive’. Another of her projects, ‘A Knock at the Door’, received critical acclaim and won the Festival Award at the Atlanta Horror Film Festival, along with nominations at FilmQuest.

Her battle with glioma

In recent years, Mack shared her journey with glioma — a particularly aggressive cancer affecting the central nervous system. Last January, she posted on Instagram about the physical impact of her diagnosis, stating: “Due to the biopsy surgery on my spinal cord, I have lost the use of my right leg and most of my left leg.” Despite her physical limitations, Mack remained hopeful, frequently sharing videos of her rehabilitation progress alongside her partner.

Diffuse midline glioma, the rare form of cancer that took Mack’s life, originates from glial cells that support the brain and spinal cord. Although gliomas are among the most common brain tumours, the diffuse midline variant is especially devastating. It tends to grow in areas crucial for vital functions — including movement, breathing, and consciousness — and its diffuse nature makes surgical treatment nearly impossible.

Medical professionals say the tumour’s resistance to radiation and chemotherapy, coupled with a lack of effective treatments, make it one of the most lethal brain cancers. While most diagnoses occur in children, Mack’s case highlights how this unpredictable disease can also impact young adults. Research into targeted therapies and genetic factors continues, though a cure remains elusive.