Actor Kenneth Mitchell, who starred in Marvel’s Captain Marvel and the television series “Star Trek: Discovery,” passed away, according to a statement his family posted on his verified social media accounts on Sunday.

The family said, “With heavy hearts, we announce the passing of Kenneth Alexander Mitchell, beloved father, husband, brother, uncle, son, and dear friend.” In 2018, Mitchell received an ALS diagnosis. In recent years, he and his family have periodically updated each other on his health. Mitchell shared a picture on Instagram in August to commemorate the fifth anniversary of his diagnosis.

“My brother commented that the store doesn’t have a happy ALS Anniversary card. But today, I want to honour the gift of life. I’m incredibly grateful that I have today ahead of me. Five years is a long time. So much gained, so much lost. A problematic period interspersed with an abundance of blessings, Mitchell penned at the time. “Friends and family, caregivers, and medical professionals who consistently come to my family’s aid are at the centre of it all—extending an abundance of love, support, care, and inspiration. That is so very beautiful. This illness is horrifying. But there are many things to be thankful for despite all the pain.

Canadian-born Mitchell accumulated over 50 credits in films and television shows during his acting career. In Marvel’s 2019 film “Captain Marvel,” he portrays Carol Danvers’ father; in the 2004 hockey movie “Miracle,” he plays an Olympic hopeful. Mitchell starred in numerous television shows, such as “Switched at Birth,” “Jericho,” and “The Astronaut Wives Club.” Mitchell portrayed the Klingons Kol, Kol-Sha, Tenavik, and Aurelio in “Star Trek: Discovery” from 2017 to 2021.

“Perspective and cultural understanding are the key factors in determining an individual’s goodness or badness,” he stated to StarTrek.com in 2017. “On our show, you’ll get to know the Klingons, and then people can judge whether or not we’re the bad guys.”

Those close to Mitchell remembered him as a “hope seeker, daydreamer, dream believer” in addition to his acting roles. In a statement, Mitchell’s family expressed gratitude for his courage in the face of illness.

“Regardless of his later disabilities, Ken discovered a higher calling to be more fully himself for his kids,” they wrote. “For five and a half years, Ken faced a series of awful challenges from ALS. In the most accurate Ken fashion, he managed to rise above each one with grace and commitment to living a whole and joyous life in each moment. Mitchell is survived by his wife, Susan, and their two young children.