Papa Bear, a football lifer. He played, coached, and administrated until the day he died.
For a long stretch of NFL history he was atop the career wins list with his 318 wins. He started the first NFL dynasty winning six NFL championships in three decades.
His eye for talent was astounding; under his care from 1920 to 1983, the Bears had more Hall of Fame players than any team. This list includes truly great players like Gale Sayers, Sid Luckman, Dick Butkus, Mike Ditka, Red Grange, and Walter Payton.
George Halas could be the single greatest Football administrator, but as for coaching he never faced AFL competition, so I have a hard time putting him number #1 or #2. But every year, the winner of the NFC hefts the George Halas trophy for good reason.
George Halas is your fifth greatest coach of all-time.