On the field, Steve McMichael was known for his massive frame, bulging biceps, tree-trunk legs, and a personality that matched it all. Across a 15-year career, he anchored the Chicago Bears‘ defense, dominated the trenches, and helped the franchise win multiple division titles. But years after football, in April 2021, he was diagnosed with Amyotrophic Lateral Sclerosis (ALS).
ALS is a neurodegenerative neuromuscular disease that leads to the progressive loss of motor neurons responsible for controlling voluntary muscle movement. Four years later, the story took a heavier turn. The Bears lost one of their icons just a year after McMichael was inducted into the Pro Football Hall of Fame. Now, another layer has emerged. It has been reported that McMichael was posthumously diagnosed with Chronic Traumatic Encephalopathy (CTE).
Breaking: Chicago Bears legend Steve “Mongo” McMichael was diagnosed with stage 3 CTE by researchers at @bu_cte. He was a key member of the Bears’ 1985 Super Bowl championship team and a Pro Football Hall of Famer. Mongo died in April 2025 after a nearly 5-year public battle with… pic.twitter.com/hbLhHtOyOf
— Concussion & CTE Foundation (@ConcussionCTEfn) April 7, 2026
Researchers at the Boston University CTE Center confirmed that he had stage three CTE out of four. It is a degenerative brain disease commonly found in athletes exposed to repeated head trauma, as well as combat veterans. The condition is associated with symptoms like mood swings, impulsive behavior, and depression, and can only be diagnosed after death.
In McMichael’s case, that diagnosis came nearly a year after his passing at 67. And the findings reinforced a growing body of research connecting CTE and ALS.
“Steve McMichael had severe CTE as well as ALS with TDP-43 inclusions typical for ALS in his brainstem and spinal cord,” said Dr. Ann McKee, director of the Boston University CTE Center and chief of neuropathology for the VA Boston Healthcare System. “There is strong evidence linking repetitive brain trauma and ALS; in our CTE brain bank, about 6% of individuals with CTE also have ALS.”
That connection has been building for years. Studies, including one from Harvard Medical School and Boston University in 2021, found that NFL players are more than four times as likely to develop ALS compared to the general population. And within CTE cases, a notable percentage also show signs of ALS, often referred to as Lou Gehrig’s disease.
And now, the league has lost another icon to ALS and CTE. Back in 2016, the former RB Kevin Turner passed away after battling ALS. Upon his death, it was revealed that the illness was triggered by CTE.
That broader pattern is exactly why McMichael’s wife, Misty McMichael, chose to share his diagnosis publicly.
“By sharing Steve’s diagnosis, we want to raise awareness of the clear connection between CTE and ALS. Too many NFL players are developing ALS during life and diagnosed with CTE after death. I donated Steve’s brain to inspire new research into the link between them.”
It’s also important to note that this was something McMichael himself supported. While he was alive and aware of his condition, he made the decision to donate his brain for research.
Now, a year after his passing, that decision is doing exactly what it was meant to do. Not just providing answers about his condition, but adding to a larger conversation about the long-term impact of the game and the link between ALS and CTE.
