Pro Football Hall of Fame defensive tackle Steve McMichael has been posthumously diagnosed with stage 3 chronic traumatic encephalopathy (CTE), researchers announced following examination of his brain tissue.

McMichael, known by the nickname "Mongo," died in 2025 at age 67 after a five-year battle with amyotrophic lateral sclerosis (ALS). His wife Misty donated his brain for research into neurodegenerative diseases.

The former Chicago Bears star was a key member of the team's legendary 1985 Super Bowl championship defense. He played 15 seasons in the NFL, spending 13 years with Chicago from 1981 to 1993 before finishing his career with the Green Bay Packers.

CTE is a progressive brain disease associated with repeated head trauma and has been found in numerous former NFL players. The condition can only be definitively diagnosed through post-mortem brain examination. Stage 3 CTE typically involves more severe symptoms and brain changes than earlier stages of the disease.

McMichael was inducted into the Pro Football Hall of Fame in 2024, shortly before his death. He was selected to two Pro Bowls during his career and was known as one of the most dominant defensive linemen of his era.