Kelley Mack, the American actress best known for her role as Addy in Season 9 of The Walking Dead, has died at the age of 33.
Her family confirmed that she passed away peacefully on Saturday, August 2, 2025, in her hometown of Cincinnati, Ohio.
The cause of death was glioma of the central nervous system, a rare and aggressive type of tumor that affects the brain and spinal cord.
Mack had been battling the illness since late 2024, following early symptoms that began with back pain.
The heartbreaking news was shared on her official Instagram account by her sister, Kathryn, who wrote:
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.
In the same post, Kathryn 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, especially when she decided to make the leap to be reunited with God.
Kelley Mack, whose full name was Kelley Lynne Klebenow, began her career in the entertainment industry at a young age after receiving a mini video camera as a birthday gift.
Her passion for storytelling led her to study cinematography at Chapman University’s Dodge College of Film and Media Arts.
Throughout her career, she appeared in over 35 acting projects and produced five others.
In addition to The Walking Dead, she had notable roles in Chicago Med, 9-1-1, and the film Broadcast Signal Intrusion.
She also worked in numerous commercials for brands like Dr. Pepper, Ross, Dairy Queen, and Chick-fil-A.
Mack documented parts of her cancer treatment journey on social media.
In a touching post from March, she shared a video of herself ringing the bell at a medical center after finishing proton radiation therapy.
Overall, this journey has not been easy, but things are getting better – improvements are tough to see when you’re in the thick of it, she wrote at the time.
She lost mobility in her legs after spinal surgery but continued rehabilitation with the help of her boyfriend Logan Lanier, who supported her through the illness.
A statement posted on the site CaringBridge remembered her as someone whose
infectious enthusiasm and dedication to her work inspired countless others in the industry and beyond.
Friends, co-stars, and fans have paid tribute to her talent and spirit. Alanna Masterson, who worked alongside her in The Walking Dead, shared,
What an incredible human. So proud to have fought alongside her in our final episode together.
Kelley Mack is survived by her parents Kristen and Lindsay Klebenow, sister Kathryn, brother Parker, grandparents Lois and Larry Klebenow, and her boyfriend Logan.
A remembrance service is planned for August 16 in Glendale, Ohio, with a larger celebration of life to take place later in Los Angeles, where she lived and worked for over a decade.
Her family described her as a sweet soul filled with warmth, courage, and creativity, someone who made everyone feel seen.
They said her memory will continue through her art, her love, and the impact she left behind. As her sister movingly noted,
She now comes to us in the form of butterflies—because, of course, she does.
