By Prosper Mene
Kelley Mack, beloved actress known for her role as Addy in Season 9 of AMC’s The Walking Dead, passed away on August 2, 2025, at the age of 33 in her hometown of Cincinnati, Ohio.
Her family confirmed that she succumbed to a rare and aggressive form of brain cancer, central nervous system glioma, specifically diffuse midline glioma, which she had been battling privately since her diagnosis in September 2024.
Born Kelley Lynne Klebenow on July 10, 1992, her passion for storytelling started at a young age when she received a mini video camera as a birthday gift. This early incident led to a prolific career, amassing 35 acting credits and five producer credits. Her breakout role as Addy, a Hilltop Colony resident in The Walking Dead (2018–2019), showcased her ability to bring depth to ensemble casts. Mack also appeared as Penelope Jacobs in Season 8 of Chicago Med (2022) and in an episode of 9-1-1 (2019). Her film roles included Broadcast Signal Intrusion (2021), Delicate Arch (2024), and the recently released Universal (2025), where she starred and served as an executive producer.
Beyond acting, Mack was a versatile talent, contributing voice-over work for high-profile projects like the Oscar-winning Spider-Man: Into the Spider-Verse (2018), where she voiced Gwen Stacy as a voice match for Hailee Steinfeld. She also appeared in national commercials for brands like Dr. Pepper, Chick-fil-A, and Rakuten, often collaborating with her mother, Kristen Klebenow, with whom she co-wrote several feature scripts, including On the Black, a 1950s-era college baseball story inspired by her grandparents.
Mack’s family shared a heartfelt statement on her Instagram, saying, “It is with indelible sadness that we are announcing the passing of our dear Kelley. Such a bright, fervent light has transitioned to the beyond, where we all eventually must go.” Her sister, Kathryn Klebenow, noted that Mack passed peacefully, surrounded by her mother, Kristen, and aunt, Karen, adding, “Kelley has already come to many of her loved ones in the form of various butterflies.” Tributes from colleagues, including The Walking Dead co-star Alanna Masterson, praised her as “an incredible human” whose talent and warmth left a lasting impact.
Despite the challenges of her illness, Mack remained resilient. In January 2025, she shared on Instagram that the biopsy surgery on her spinal cord had impaired her mobility, requiring a walker and wheelchair. By March, she celebrated small victories, such as re-learning to walk up stairs, a testament to her determination. “I am very grateful to have such a supportive and loving family and boyfriend, who have been with me every second of this process,” she wrote, expressing her faith and trust in her journey.
A Cincinnati native, Mack graduated from Hinsdale Central High School in 2010 and earned a bachelor’s degree in cinematography from Chapman University’s Dodge College of Film and Media Arts in 2014. She was an accomplished college tennis player, who loved hiking, pickleball, biking, playing piano, and traveling. She is survived by her parents, Kristen and Lindsay Klebenow; her sister, Kathryn; her brother, Parker, also an actor; her grandparents, Lois and Larry Klebenow; and her boyfriend, Logan Lanier.
A remembrance gathering is scheduled for August 16, 2025, in Glendale, Ohio, with a larger celebration of life planned in Los Angeles, where Mack lived and worked for the past 11 years.
Her family described her as “gentle, radiant, and full of purpose,” noting that her legacy will endure through her contributions to film and television and the love she shared with those around her.
Mack’s vibrant spirit and dedication to her craft inspired countless others, leaving an indelible mark on the entertainment industry and the hearts of her loved ones.
