How did Kenneth Mitchell die? Marvel and Star Trek actor's cause of death explained

Actor Kenneth Mitchell, known for his roles in Star Trek: Discovery and Captain Marvel, passed away on February 24 at the age of 49 after battling ALS (Amyotrophic Lateral Sclerosis), a motor neuron disease, for five and a half years. His family, in their tribute to him on Instagram, called him "an inspirational work of art to all the hearts he touched."

Throughout his career, Mitchell portrayed four different characters: Kol, Kol-Sha, Tenavik, and Aurellio in three seasons of Star Trek: Discovery on Paramount. He also played World War II pilot Deke Slayton in ABC's The Astronaut Wives Club and a younger version of Captain Marvel's father in a flashback in Marvel's Captain Marvel.

In an interview with PEOPLE in 2020, Kenneth talked about his illness and revealed how shocking it was to receive the diagnosis.

"The moment that they told us it was [ALS], it was like I was in my own movie. That’s what it felt like, like I was watching that scene where someone is being told that they have a terminal illness. It was just a complete disbelief, a shock."

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Kenneth Mitchell's battle with ALS explained

According to his family's post on Instagram, Kenneth Mitchell had been battling ALS for more than 5 years. Describing him as a source of inspiration, they highlighted his ability to confront challenges with a unique style and embrace each day as a precious gift.

Kenneth fought a fatal neurological disease that affects nerve cells in the brain and spinal cord, resulting in a gradual loss of muscle control. In his 2020 interview with PEOPLE, he said he was having continual twitches in his muscles, which he thought was because of a pinched nerve.

Using a wheelchair for his role (Image via mr_kenneth_mitchell@Instagram)

The diagnosis of ALS, he said, came as a complete shock. He admitted that he couldn't hide his disease since he had to use a wheelchair for some part of it. And also because he wanted to spread awareness of ALS.

"I think there’s something I can offer and I want to be a part of that. “If I can inspire one person that would mean a lot to me."

In a 2021 Instagram post, he thanked his fans for showing love to his character, Aurellio, who uses a wheelchair in Star Trek. He said that the support of his Discovery family had made him believe in the possibility.

"It was a special collaboration with my Discovery family that injected me with heaps of Love & Inspiration during my tough battle with ALS. A reminder that despite ones [sic] disabilities there is always room for possibility & ability. Incredibly grateful for the inclusion."

Last year, he posted a picture on Instagram of him at the beach watching the sunset. He described the disease as "horrific," but also said that there was a lot to be grateful for too.

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Kenneth Mitchell's major contribution to Marvel and the Star Trek universe

Captain Marvel star (Image via mr_kenneth_mitchell@Instagram)

Toronto-born Kenneth Mitchell got his start in the film industry by landing the role of professional ice hockey player Ralph Cox in Disney's 2004 Miracle. In 2006, he took on the role of mayor-turned-sheriff Eric Green on CBS' Jericho, marking his first series regular role. His most recent role was as Joe in FX/Hulu's The Old Man in 2022.

In the 2019 Marvel film Captain Marvel, Mitchell portrayed Joseph Danvers, the father of Brie Larson's character Carol. In 2015, he played World War II pilot Deke Slayton in ABC's The Astronaut Wives Club.

He made significant contributions to the Star Trek franchise, portraying various characters in Star Trek: Discovery, including Klingons Kol, Kol-Sha, and Tenavik. In the third season, he needed a wheelchair to move around. So he played Aurellio, who used a hoverchair (a modern wheelchair).

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Kenneth Mitchell is survived by his wife, Susan Pratt, his children, Lilah and Kallum, and his parents.