Kelley Mack, an American actress recognized for her roles on popular television series The Walking Dead and Chicago Med, has died after a battle with cancer. She was 33 years old.
Mack’s death was confirmed Tuesday by her sister, Kathryn, in a heartfelt statement shared on the actress’s Instagram page. According to the post, Mack passed away on Saturday surrounded by loved ones. NBC News later reported that the actress died from diffuse midline glioma, a rare and aggressive form of cancer that affects the central nervous system.
“It is with indelible sadness that we announce the passing of our dear Kelley,” her sister wrote. “Such a bright, fervent light has transitioned beyond this world. Kelley was deeply loved, fiercely brave, and strong beyond measure. She would want everyone to know how much she loved them.”
Born Kelley Lynne Klebenow in Cincinnati, Ohio, Mack developed an interest in performing at a young age. According to her biography, she began acting in commercials as a child, gaining early exposure to the entertainment industry. A video camera she received during her youth helped spark a lifelong passion for storytelling, filmmaking, and creative expression.
Mack later pursued acting professionally, building a résumé that included both television and film work. She became widely known for her appearance as Addy in Season 9 of AMC’s long-running zombie drama The Walking Dead. Although her role was brief, it placed her within one of television’s most successful franchises and introduced her to a broader global audience.
She also appeared on NBC’s medical drama Chicago Med, portraying the character Penelope Jacobs. Her performances were often described as grounded and emotionally resonant, reflecting her dedication to craft and her ability to bring depth to supporting roles.
Beyond acting, Mack was a multifaceted artist. She worked as a voice actor and was actively involved behind the camera as a producer and cinematographer. Her film A Knock at the Door received critical attention and won accolades at the Atlanta Horror Film Festival in 2022, highlighting her growing influence as an emerging filmmaker.
In late 2024, Mack began sharing personal health updates with her followers on social media. She revealed that she had been experiencing persistent lower back pain, which initially appeared unexplained. In January, she announced that she had been diagnosed with diffuse midline glioma.
Diffuse midline glioma is a rare cancer that develops in the brain or spinal cord and primarily affects the central nervous system. According to the National Cancer Institute, the disease is particularly difficult to treat due to its location and aggressive nature. Despite the diagnosis, Mack continued to share messages of resilience, honesty, and gratitude with her supporters.
Friends, colleagues, and fans have since taken to social media to express their condolences and to honor her life and work. Many described Mack as kind, generous, and deeply committed to her creative pursuits, noting her willingness to support fellow artists and uplift others within the industry.
“Kelley’s legacy will live on through her contributions to film and television and through the countless lives she touched,” her obituary states. “She will be remembered for her talent, her compassion, and her vibrant spirit.”
Mack is survived by her parents, two siblings, and her boyfriend. A celebration of her life is scheduled to take place this Saturday in Ohio, where family and friends will gather to honor her memory.
Though her career was cut tragically short, Kelley Mack leaves behind a body of work that reflects her passion for storytelling and her dedication to her art. Her death marks a profound loss for the entertainment community and for those who knew her personally, but her impact will continue to be felt through the stories she helped bring to life.
