The Walking Dead Star Kelley Mack Dies at 33 After Brave Cancer Battle

Kelley Mack, best known for her role as Addy on AMC’s The Walking Dead, has died at the age of 33 after a battle with diffuse midline glioma, a rare and aggressive form of brain cancer. Her family confirmed that she passed away peacefully in Cincinnati, surrounded by loved ones. The Walking Dead Star Kelley Mack Dies

The Walking Dead Star Kelley Mack Dies

Early Life and Career

Kelley Mack, born Kelley Lynne Klebenow on July 10, 1992, in Ohio, began her acting and filmmaking career after graduating from Chapman University in 2014 with a degree in cinematography. She initially appeared in commercials and short films before landing more prominent roles on television.

She gained recognition for her portrayal of Addy in Season 9 of The Walking Dead, where she played a member of the Hilltop community. Her other television credits include appearances on Chicago Med and 9-1-1. In addition to acting, Mack worked behind the scenes as a producer and filmmaker. Her independent projects include the short films The Elephant in the Room and Unnatural. At the time of her diagnosis, she had recently completed work on an independent feature titled Universal, which she wrote, produced, and starred in.

Medical Diagnosis and Illness

In late 2024, Mack began experiencing symptoms including persistent lower back pain and neuropathic itching. She underwent medical testing and was diagnosed with diffuse midline glioma, a rare form of astrocytoma typically found in children. The tumor was located near her spine, and a biopsy led to mobility loss in her legs. She used both a walker and wheelchair during the course of her treatment.

Despite undergoing radiation and chemotherapy, the disease progressed rapidly. Mack’s health continued to decline throughout the first half of 2025. She documented parts of her experience publicly, raising awareness about her condition.

Legacy and Memorial Plans

Mack’s career included 35 acting credits and five producer credits. Her performances spanned both screen and stage, and she was active in the independent film community. She was known for her dual work in front of and behind the camera.

A memorial service is scheduled for August 16, 2025, in Glendale, Ohio. A separate celebration of life will be held in Los Angeles at a later date.

Mack is survived by her mother, extended family members, and a wide circle of collaborators and friends in the entertainment industry.

Diffuse midline glioma is a fast-growing, high-grade brain tumor that primarily affects children and young adults. It typically forms in the spinal cord or brainstem and has a poor prognosis. The condition is classified as a Grade IV glioma and is considered terminal in most cases due to its location and resistance to standard treatments.

For more information about the condition and ongoing research efforts, resources are available through the American Brain Tumor Association and related organizations.

Kelley Mack is remembered not only for her contributions to film and television, but also for her determination and grace in the face of a devastating illness. She leaves behind a growing body of creative work and a lasting impression on her colleagues and audience.

At this time, thoughts and prayers are with her family, friends, and fans as they mourn her passing and honor her legacy.