Actress Kelley Mack, widely recognized for her compelling portrayals in the post-apocalyptic horror series “The Walking Dead” and the medical drama “Chicago Med,” has tragically passed away at the age of 33. A representative for Mack confirmed her death to ABC News, stating simply, “She will be sorely missed.” Mack passed away peacefully on August 2 in her hometown of Cincinnati, Ohio, with her loving mother, Kristen, and steadfast aunt, Karen, by her side, after a courageous battle with a glioma, a severe type of central nervous system tumor. This profound loss marks the end of a vibrant career that saw her contribute to television, film, and commercial work, leaving an indelible impact on both her colleagues and devoted fanbase.
Mack’s family released a heartfelt online statement announcing her passing, sharing, “It is with indelible sadness that we announce the passing of our dear Kelley.” They eloquently described her as “a bright, fervent light,” emphasizing her profound effect on those around her. The statement continued with a touching image of her spiritual presence, noting, “Kelley has already appeared to many of her loved ones in the form of various butterflies 🦋 ❤️.” This sentiment underscored the depth of their grief and love, concluding, “She will be missed by so many to a depth that words cannot express.”
Mack first revealed her health struggles in a candid Instagram post in January, detailing the onset of symptoms in the previous fall. She described experiencing “persistent lower back pain” starting in September, initially believing she had simply slipped a disc. Weeks later, she developed “neuropathic itching in my right quad,” followed by debilitating “shooting pains in my legs and back.” The intensity of this pain forced her to abandon a traditional bed, leading her to sleep in a recliner for a month because, as she explained, “lying down was too painful.”
The severity of her condition necessitated emergency MRIs performed at a hospital on Thanksgiving Eve, which subsequently “revealed an abnormal mass in her spinal cord.” This critical discovery led to her formal diagnosis of diffuse midline glioma, a condition she openly described as “an extremely rare type of astrocytoma cancer.” The invasive biopsy surgery on her spinal cord, a necessary step for diagnosis, had severe consequences, causing her to lose “the use of her right leg and most of her left leg,” resulting in her reliance on a walker and a wheelchair for mobility.
In mid-January, Mack began undergoing proton radiation treatments in Cincinnati, a challenging phase she remarkably framed with a sense of wonder, writing, “It felt like I was filming an episode of my new TV show, set on a spaceship floating somewhere in our infinite galaxy.” Despite the formidable nature of her illness and continued pain, her resilience shone through as she shared a video in March showing herself walking up stairs, a moment she celebrated as “a big deal for her.” She acknowledged the emotional toll in an April CaringBridge update, stating, “Some days are challenging,” but maintained an unwavering positive outlook, asserting, “We continue to feel confident in our path forward, in God, and in our love for each other, all leading us to overcome.” By July, however, her condition had unfortunately progressed, and she was receiving respite care, described as “the toughest part of her journey.”
According to the National Cancer Institute, diffuse midline gliomas are highly aggressive tumors that originate in the primary central nervous system, encompassing crucial areas such as the brain or spinal cord. These formidable growths represent “a rare subtype of glial tumors,” with an estimated 3,940 individuals currently living with them across the U.S. The diverse symptoms associated with these gliomas can include double vision, challenges with swallowing, and a noticeable loss of balance or weakness affecting one or both sides of the body. While most frequently identified in children, the National Cancer Institute also confirms their occurrence in adults.
The National Cancer Institute outlines various treatment modalities for individuals diagnosed with diffuse midline gliomas, including surgical intervention, chemotherapy, radiation therapy, or the administration of targeted medications. Despite these options, the relative five-year survival rate for this condition stands at 42.2 percent. It is important to note that survival outcomes are highly dependent on numerous factors, such as an individual’s age at diagnosis and the specific grade of the tumor, underscoring the complex nature of this rare cancer.
Born Kelley Lynne Klebenow in Cincinnati, Ohio, on July 10, 1992, Mack had a geographically diverse upbringing, with her family residing in towns across Ohio, Missouri, Connecticut, North Carolina, and Illinois. She laid the foundation for her future career by graduating from Hinsdale Central High School in 2010. Mack’s profound love for storytelling was ignited at a remarkably young age, specifically when she received a mini video camera as a birthday gift, an event her family credits with sparking “a lifelong passion for the arts.” This early fascination led her to begin acting in commercials during her childhood, paving the way for a distinguished professional journey.
Mack further honed her artistic talents at Chapman University’s Dodge College of Film and Media Arts in Orange, California, where she earned a bachelor’s degree in cinematography in 2014. Upon graduation, she relocated to Los Angeles, establishing her professional base there for the following decade. Her talent gained early recognition with her debut role as Chloe in the 2008 independent film “The Elephant Garden,” a performance that earned her an Acting Award from the Tisch School of the Arts. The film itself also received accolades, winning the Student Visionary Award at the Tribeca Film Festival, highlighting Mack’s impactful entrance into the industry.
Kelley Mack became widely recognizable for her role as Addy in the ninth season of AMC’s acclaimed post-apocalyptic zombie drama “The Walking Dead.” She appeared in a five-episode arc of the series from 2018 to 2019, making a notable impression on viewers. As Addy, she was introduced as one of the young residents of Hilltop, who developed a crush on the character Henry while he harbored affections for Lydia. Her character’s storyline culminated tragically when Addy’s reanimated head, along with those of Henry and other brave individuals kidnapped by Alpha, ended up on a pike at the border of the Whisperers’ territory after they bravely but unsuccessfully fought for their lives.
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Beyond her pivotal role in “The Walking Dead,” Mack also showcased her acting prowess in other prominent television series. She portrayed Penelope Jacobs in the eighth season of NBC’s “Chicago Med,” a medical drama that is scheduled to return for its 11th season this fall. Additionally, Mack made an appearance on FOX’s procedural drama “9-1-1” in 2019, further diversifying her television portfolio. Her ability to seamlessly transition between genres highlighted her versatility as an actress, contributing to a total of 35 acting credits throughout her career.
Mack’s filmography includes several notable roles across different genres. She was known for her part as Alice in the 2021 horror film “Broadcast Signal Intrusion,” showcasing her depth in suspenseful narratives. In 2024, she appeared in “Mr. Manhattan” and also as Wilda in “Delicate Arch,” further expanding her presence on the big screen. Mack has also been actively promoting the upcoming 2025 film “Universal” on Instagram in recent months, a project in which she not only starred but also contributed as an executive producer, demonstrating her commitment behind the camera as well.
Mack’s captivating presence extended to numerous national commercial campaigns, making her a familiar face to many viewers. She was featured prominently as Becky in the popular “Fansville” ads for Dr Pepper. Her commercial appearances also included campaigns for major brands such as Ross Stores, Dairy Queen, and Chick-fil-A. In a poignant collaboration, she filmed a Rakuten commercial with her mother, Kristen, as recently as April, showcasing their bond. Beyond her on-screen commercial work, Mack was a versatile voice-over artist, lending her distinctive voice to spots for Hyundai Ioniq, Budweiser, Credit Karma, and contributing to the Oscar-winning animated hit “Spider-Man: Into the Spider-Verse.”
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Adding to her extensive acting resume, Kelley Mack also held five producer credits, demonstrating her comprehensive involvement in filmmaking. She collaborated closely with her mother, Kristen Klebenow, on the development of several full-length scripts. Among these notable projects was “On The Black,” a compelling 1950s-era college baseball story that drew inspiration from the experiences of her maternal grandparents, who attended Ohio University. This particular film, distributed by AMC’s Shudder, garnered significant industry recognition, earning the prestigious Jury Choice Award at the Atlanta Horror Film Festival, a testament to her creative and production capabilities.
Kelley Mack was the oldest of three children, and her family formed a central part of her life and support system. She is survived by her loving parents, Kristen and Lindsay Klebenow, her sister Kathryn, and her brother Parker Mack, who is also an actor. Her grandparents, Lois and Larry Klebenow, also mourn her passing, along with her devoted boyfriend, Logan Lanier. The family’s collective statement underscored Mack’s innate qualities, describing her as known for “her warmth, creativity, and unwavering support for those around her.” They added that “Her infectious enthusiasm and dedication to her work inspired countless others in the industry and beyond,” painting a picture of a truly remarkable individual.
The news of Mack’s passing elicited an outpouring of condolences from colleagues, friends, and admirers, who universally remembered her as “talented” and a “sweet soul.” Alanna Masterson, who shared the screen with Mack in “The Walking Dead,” offered a heartfelt tribute, reflecting, “What an incredible human. So proud to have fought alongside her in our final episode together.” Mack’s sister, Kathryn Klebenow, shared deeply personal sentiments on Instagram, assuring followers, “She would want you all to know how much she loves you.” Kathryn further articulated the immense strength her sister possessed, stating, “And as her sister, I want you all to know how brave that tough person was, especially when she decided to make the leap to be reunited with God. I’m so proud of her.”
Outside of her professional endeavors, Mack cultivated a rich and active personal life, embracing an adventurous spirit. She found immense joy in various outdoor activities, including hiking, biking, and playing tennis, which reflected her dynamic personality. Mack also possessed musical talent, enjoying playing the piano, further illustrating her diverse interests and creative inclinations. Friends consistently spoke of her remarkable ability to infuse “energy and joy” into every pursuit, highlighting her vibrant and inspiring nature. Her family’s statement further affirmed her deep connection to loved ones, emphasizing that she “cherished time with her family and friends, finding joy in collaboration and storytelling,” which collectively contributed to her reputation as a genuinely warm and inspiring individual.
Kelley Mack’s profound legacy, as articulated by her family, “will live on through her contributions to film and television, and in the hearts of those who loved her.” They passionately affirmed that she “will be deeply missed and forever remembered for her talent, kindness, and vibrant spirit,” a testament to the lasting impression she made. To honor her life, a “recognition and remembrance” ceremony is scheduled for August 16 in Glendale, Ohio. Additionally, a separate celebration of life will be held in Los Angeles at a date yet to be determined, allowing her extensive network of friends, colleagues, and admirers on both coasts to come together and celebrate the remarkable life of Kelley Mack.
