Kelley Mack, best known for her role as Addy on The Walking Dead, died Saturday in her hometown of Cincinnati, Ohio, at age 33 after a battle with glioma, a rare and aggressive form of cancer affecting the central nervous system.
Her sister, Kathryn Klebenow, shared the news Tuesday via Mack’s Instagram, writing, “It is with indelible sadness that we are announcing the passing of our dear Kelley.” She added that Mack passed peacefully with her mother Kristen and aunt Karen by her side, and has since “come to many of her loved ones in the form of various butterflies.”
Mack, whose full name was Kelley Lynne Klebenow, first experienced persistent back pain in October 2024. After a hospital visit in November revealed a spinal mass, she was diagnosed in January with diffuse midline glioma. The cancer and resulting biopsy left her partially paralyzed, and she openly documented her recovery journey online, including relearning to walk.
She began acting in commercials as a child, and her first film role in The Elephant Garden won a Student Visionary Award at the 2008 Tribeca Film Festival. In addition to her five-episode arc on The Walking Dead, Mack guest-starred on Chicago Med, 9-1-1, and also produced several short films.
“She was so brave, especially when she made the leap to be reunited with God. I’m so f–king proud of her,” Kathryn wrote.
Mack is survived by her parents Kristen and Lindsay Klebenow, sister Kathryn, brother Parker, and grandparents Lois and Larry Klebenow. Her funeral will be held August 16 in Glendale, Ohio.
