What happened to The Walking Dead actress Kelley Mack? Explained

Kelley Mack passed away at the age of 33 on August 2, 2025, in Cincinnati, following a diagnosis of central nervous system glioma. Her family shared the news via a formal obituary and confirmed it on her official Instagram, where they described that she “passed away peacefully.”

The actor, best known to many as Addy on season 9 of The Walking Dead, had built a steady résumé across television and film, including appearances on Chicago Med and 9-1-1, and roles in features such as Broadcast Signal Intrusion and Delicate Arch.

Reports note that Kelley Mack, born Kelley Klebenow, amassed 35 acting credits and five producer credits and was slated to appear posthumously as “Ricky” in the upcoming feature Universal. As per the People report dated August 5, 2025, her obituary also reflected the person behind the credits and the community around her at the end of her life.

What happened to Kelley Mack?

Kelley Mack’s family said she passed away on Saturday, August 2, 2025, in her birthplace of Cincinnati, following a diagnosis of glioma of the central nervous system. The announcement came first through a CaringBridge obituary and a coordinated post on her verified Instagram account on Tuesday, August 5.

The obituary stated the 33-year-old “passed away peacefully,” and Entertainment Weekly noted that the Instagram post announcing her death was written by her younger sister, Kathryn. In their initial messages, the family chose language that emphasized love and dignity. The Instagram announcement read:

“It is with indelible sadness that we are announcing the passing of our dear Kelley.”

As per the People report dated August 5, 2025, the obituary added:

“She cherished time with her family and friends, finding joy in collaboration and storytelling.”

Kathryn’s fuller tribute about her sister’s final moments and their family’s faith imagery. As per Entertainment Weekly's report dated August 5, 2025:

“Kelley passed peacefully on Saturday evening with her loving mother Kristen and steadfast aunt Karen present.”

In a separate line from the same tribute, Kathryn closed with,

“I’m so f---ing proud of her.”

Who was Kelley Mack on The Walking Dead?

Kelley Mack appeared as Addy, a Hilltop Colony resident, across five episodes of The Walking Dead season 9 (2019). In television, she also portrayed Penelope Jacobs in Chicago Med (season 8) and had an appearance on 9-1-1.

Her film work included Alice in Broadcast Signal Intrusion (2021) and Wilda in Delicate Arch (2024). She also voice-matched Hailee Steinfeld’s Gwen Stacy in promotional materials tied to Spider-Man: Into the Spider-Verse and booked commercial work for brands including Dr Pepper, Dairy Queen, Ross, and Chick-fil-A.

Across industry coverage, Kelley Mack is remembered as a working actor who steadily built credits in Los Angeles over 11 years. Her career also highlights a forthcoming role as Ricky in Universal (writer-director Stephen Portland), along with screenwriting projects she developed with her mother.

What did Kelley Mack’s family say?

In addition to confirming the date and place of death, the obituary and social media tributes focused on the qualities that defined Kelley Mack off-screen: her warmth, collaboration, and the relationships she nurtured. As per the People report dated August 5, 2025, the obituary described how she loved.

“hiking, pickleball, biking, playing piano and traveling.”

It emphasized that she cherished time with loved ones. The same report lists those she leaves behind: parents Kristen and Lindsay Klebenow, siblings Kathryn and Parker (also an actor), grandparents Lois and Larry, and her boyfriend, Logan.

Kelley is being memorialized as an actor whose career spanned network television, indie films, voice work, and commercials, and as a daughter, sister, partner, and friend, remembered for her creativity and care.

Stay tuned for more updates.