23. Dick LeBeau
LeBeau defines how you can be a brilliant specialist coach but struggle with the top job. Active at field level for 59 consecutive seasons, LeBeau is one of the greatest defensive coordinators of all time. Steelers’ players called him ‘Coach Dad’ and had nothing but love for the defensive genius.

Unfortunately, his tactical ability didn’t translate to being a head coach. His only time in the role was with the Cincinnati Bengals from 2000-02. But that came to an abrupt end after three dismal seasons. However, LeBeau’s legacy remains intact. The ‘zone blitz’ defense is his most famous innovation.