On August 2, 2025, Kelley Mack, beloved actress known for her role as Addy in Season 9 of The Walking Dead, passed away at the age of 33 in her hometown of Cincinnati, Ohio, after a courageous battle with glioma of the central nervous system. Her family announced the heartbreaking news on Instagram on August 5, describing her as a “bright, fervent light” who “passed away peacefully” surrounded by loved ones. The news sent shockwaves through the entertainment industry, with tributes pouring in from co-stars, fans, and colleagues who celebrated her talent, warmth, and vibrant spirit. Mack’s legacy, spanning 35 acting credits and five producer roles, continues to inspire, with her final project, Universal, set for posthumous release. This article explores Mack’s remarkable career, her personal journey, and the outpouring of love following her passing.
A Rising Star’s Journey in Hollywood
Born Kelley Lynne Klebenow on July 10, 1992, in Cincinnati, Ohio, Mack’s passion for storytelling was ignited at a young age when she received a mini video camera as a birthday gift. This sparked a lifelong love for acting and filmmaking, leading her to perform in commercials as a child. Her first major role came at 16, playing Chloe in The Elephant Garden (2008), a short film that won the Student Visionary Award at the Tribeca Film Festival and earned her an Acting Award from NYU’s Tisch School of the Arts. This early recognition set the stage for a versatile career that blended acting, producing, and screenwriting.
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. Her education complemented her natural talent, allowing her to excel both in front of and behind the camera. Over the past 11 years, she lived in Los Angeles, building a robust career with roles in television, film, commercials, and voice-over work. Her IMDb profile lists 35 acting credits, including standout performances as Addy in The Walking Dead (2018–2019), Penelope Jacobs in Season 8 of Chicago Med (2022), and a guest spot on 9-1-1 (2019). She also voiced Gwen Stacy as a voice match for Hailee Steinfeld in the Oscar-winning Spider-Man: Into the Spider-Verse (2018) and a 2024 Hyundai Ioniq commercial.
Mack’s film roles included Alice in the psychological thriller Broadcast Signal Intrusion (2021) opposite Harry Shum Jr., Wilda in Delicate Arch (2024), and Ricky in the upcoming Universal (2025), where she also served as executive producer. Her producing credits, such as the 2016 short A Knock at the Door, which won the Festival Award at the Atlanta Horror Film Festival, showcased her multifaceted talent. She also wrote several feature scripts with her mother, Kristen Klebenow, including On the Black, a 1950s-era college baseball story inspired by her grandparents’ time at Ohio University.
A Memorable Role in The Walking Dead
Mack’s most prominent role was as Addy, a resident of the Hilltop Colony, in five episodes of The Walking Dead Season 9 (2018–2019). Her character appeared in the season’s finale, where Addy and 10 others were abducted by the Whisperers, a pivotal moment in the series. Her performance, though brief, left a lasting impression, with co-star Alanna Masterson, who played Tara Chambler, writing on Instagram, “What an incredible human. So proud to have fought alongside her in our final episode together.” Director Michael Satrazemis added, “I was lucky enough to create with Kelley on TWD. A bright light on every level.” Fans on X echoed this sentiment, with @TWDfanatic12 posting, “Kelley Mack brought so much heart to Addy. Her scenes in TWD were unforgettable.”
Her work extended beyond The Walking Dead, with guest appearances in miniseries like Unusual Suspects (2015), Grayson: Earth One (2015), Not Your Average Joe (2016), and Unscrewed (2016). Her commercial work for brands like Dr. Pepper, Ross Stores, Budweiser, Dairy Queen, and Chick-fil-A, often alongside her mother, showcased her versatility. Mack’s ability to bring depth to both dramatic and comedic roles made her a sought-after talent, with her Chicago Med role as Penelope Jacobs earning praise for its emotional nuance.
A Courageous Battle with Glioma
In September 2024, Mack publicly shared her diagnosis of central nervous system glioma, a rare and aggressive brain cancer, via Instagram. Described as a diffuse midline glioma by her family, the tumor affected her brain and spinal cord, leading to a challenging health journey. A CaringBridge page was established to provide updates, and in March 2025, Mack shared that she had completed proton radiation treatment in Florida, writing, “The mental and emotional support from my loved ones keeps me in check, even when I’m feeling physically out of whack.” Despite her illness, she remained active, starring in Universal and sharing her passion for storytelling, noting in a 2022 Instagram post, “I love acting so much and it warms me to know when others are touched by the stories I’m so lucky to be a part of sharing.”
Mack passed away peacefully on August 2, 2025, with her mother, Kristen, and aunt Karen by her side. Her family’s Instagram statement read, “Kelley has already come to many of her loved ones in the form of various butterflies 🦋 ❤️. She will be missed by so many to depths that words cannot express.” Her sister, Kathryn Klebenow, added, “She would want you all to know how much she loves you. And as her sister, I want you all to know how brave that tough SOB was.” The butterfly imagery resonated with fans, with one X user, @FilmFanatic88, tweeting, “Kelley Mack as a butterfly is so fitting—her spirit was that free and beautiful.”
A Life Full of Passion and Joy
Beyond her professional achievements, Mack was remembered for her vibrant personality and diverse interests. An accomplished college tennis player, she loved hiking, pickleball, biking, playing piano, and traveling. Her family described her as a lover of dark chocolate, sports, bourbon, popcorn, fantasy football, country music, and speaking in a British accent. A lifelong smoker, she embraced life with an infectious enthusiasm that inspired those around her. Her Universal co-star Rosa Robson commented on Instagram, “Kelley’s energy lit up every set. Her smile was contagious.” Comedian Chinedu Unaka added, “Such an extremely talented and kind person. RIP Kelley, you’ll be missed.”
Mack’s close-knit family, including her parents, Kristen and Lindsay Klebenow, sister Kathryn, brother Parker (also an actor), grandparents Lois and Larry, and boyfriend Logan Lanier, were her rock. She often collaborated with her mother on screenwriting projects, blending their creative passions. Her family noted her dedication to storytelling, with a CaringBridge statement saying, “Her vibrant spirit, creative passion, and dedication to storytelling left an indelible mark on those who knew her and the audiences she captivated.” A celebration of her life is planned for August 16 at the Glendale Lyceum in Glendale, Ohio, with a second memorial in Los Angeles for her industry friends and colleagues.
A Lasting Legacy
Mack’s passing has left a void in the entertainment world, but her legacy endures through her work and the lives she touched. Her role in Universal, set to screen at the Portland Festival of Cinema, Animation and Technology on August 10 and the Chain NYC Film Festival on August 11, will serve as a final testament to her talent. The film, a comedy-drama-sci-fi about academics interrupted by a historic discovery, reflects Mack’s love for diverse storytelling. Her Walking Dead co-star Gustavo Gomez wrote, “This is heartbreaking. I feel so lucky that our paths crossed. Your bright light will always shine on.”
Fans on X and Reddit mourned her loss, with posts like, “Kelley Mack’s Addy was small but mighty in TWD. Her talent was unreal,” and “33 is too young. Her work in Chicago Med and Universal showed she was going places.” The outpouring of tributes underscores her impact, with The Walking Dead’s official X account, @WalkingDead_AMC, remaining silent but fans filling the void with memories of her contributions. Her openness about her cancer battle, shared through social media, inspired others, with one Reddit user writing, “Kelley’s courage in sharing her journey was as powerful as her acting.”
A Bright Light Extinguished Too Soon
Kelley Mack’s death at 33 is a profound loss, but her vibrant spirit and creative contributions will live on. From her breakout role in The Elephant Garden to her memorable turn as Addy in The Walking Dead, she brought warmth and authenticity to every project. Her battle with glioma, fought with bravery and grace, and her love for storytelling, family, and life’s simple joys—butterflies, tennis, and music—paint a picture of a woman who lived fully. As her family prepares to honor her in Ohio and Los Angeles, Mack’s legacy as a talented actress, producer, and human being will continue to inspire. In the words of her sister, Kathryn, “Kelley was a tough SOB,” and her light will shine on through the stories she told and the hearts she touched.
