The game of football has no James Naismith, a single father to whom every idea can ultimately be traced. The game evolved from rugby and the (probably drunken) minds of those Rutgers and Princeton students back in 1869.
Ever since then, every idea, every new scheme, has been a mutation from an idea some other coach borrowed from another coach, who in turn took another coach's idea and put his own twist on an idea he got from someone else. And on and on it goes.
That said, there are some coaches whose ideas, clearly, had an influence that outsized their own careers. In today's college game those coaches would be Hayden Fry, Mike Leach and Nick Saban.
In the NFL, they are Marty Schottenheimer, Bill Parcells and Bill Walsh.
The Wall Street Journal published an extensive research project detailing the connections between every modern NFL coach, with complicated methodology. How complicated?
In short: Schottenheimer, Parcells and Walsh each had 12 future head coaches work under them, and the trio served as the quote-unquote coaching grandfathers of another 85 future NFL head coaches.
Among those names? Bill Belichick, Tom Coughlin, Mike McCarthy, Sean Payton and John Harbaugh. You know, just five of the last six Super Bowl winners.