Kelley Mack, an actress best known for her role as Addy on the television series The Walking Dead, died last weekend, her family announced on Tuesday. She was 33.
Mack was diagnosed with glioma, an aggressive tumor that affects the central nervous system, last year.
“It is with indelible sadness that we are announcing the passing of our dear Kelley,” her sister, Kathryn Klebenow, said in a statement posted to her Instagram page. “Such a bright, fervent light has transitioned to the beyond, where we all eventually must go.”
Mack “passed peacefully” on Saturday evening surrounded by loved ones at her home in Cincinnati, Klebenow’s note said.
She is survived by Kathryn; her brother, Parker; her parents, Kristen and Lindsay Klebenow; her grandparents Lois and Larry Klebenow; and her boyfriend, Logan Lanier.
“She would want you all to know how much she loves you,” Klebenow added. “And as her sister, I want you all to know how brave that tough SOB was, especially when she decided to make the leap to be reunited with God. I’m so f***ing proud of her.
What is glioma?
According to the Mayo Clinic, a glioma is a growth of cells that starts in the brain or spinal cord.
The cells eventually form a tumor that “can grow to press on brain or spinal cord tissue,” according to the Mayo Clinic.
The tumors can be benign or malignant, and symptoms can include headaches, nausea, seizures, fatigue, or weakness in the arms or legs, depending on which part of the brain or spinal cord is affected.
In January, Mack revealed in an Instagram post that she had started experiencing “persistent lower back pain” in fall 2024, which led her to believe she had slipped a disc.
“A few weeks later, I had neuropathic itching in my right quad,” she explained. “And then, the shooting pains in my legs and back began, which resulted in me having to sleep in a recliner for a month because laying down was too painful.”
The day before Thanksgiving, she had an emergency MRI, which revealed an abnormal mass in her spinal cord. After having biopsy surgery on her spinal cord, she said she lost most of the use of her legs, “so I now get around with a walker and a wheelchair.”
She was diagnosed with astrocytoma, or diffuse midline glioma, a rare type of cancerous tumor, and began radiation treatment in January.
A ‘love for storytelling’
Kelley Mack as Addy in a scene from The Walking Dead. (AMC)
Mack was born Kelley Lynne Klebenow on July 10, 1992, in Cincinnati.
According to a bio posted by her family on the Caring Bridge website, Kelley’s “love for storytelling” began at a young age when she was given a mini video camera as a birthday gift.
“This sparked a lifelong passion for the arts, leading her to begin acting in commercials as a child.”
After graduating high school in Hinsdale, Ill., she enrolled at the Dodge College of Film and Media Arts at Chapman University in Orange, Calif., where she earned a bachelor’s degree in cinematography in 2014.
According to IMDB, Mack has 35 acting credits, including The Walking Dead, Chicago Med and 9-1-1.
‘An incredible human’
Kelley Mack at the Chicago International Film Festival in 2021. (Barry Brecheisen/Getty Images)
Tributes have begun to pour in from fans, friends and fellow actors.
“What an incredible human,’ Alanna Masterson, who costarred with Mack in The Walking Dead, wrote on Instagram. “So proud to have fought alongside her in our final episode together.”
Mack’s family said it will host a “celebration and recognition of Kelley’s life” at the Glendale Lyceum in Glendale, Ohio, on Aug. 16. The family is also planning to hold a celebration of Mack’s life at a future date in the Los Angeles area.
Kelley Mack at the premiere of Broadcast Signal Intrusion in L.A. in 2021. (Amanda Edwards/Getty Images)
