Case For: Two-time NFL Coach of The Year (1959,1961). Two-time Super Bowl Champion (Super Bowl I, Super Bowl II), 6 Time NFL Champion (1956,1961,1962,1965, and the aforementioned Super Bowls), .728 win percentage, Green Bay Packers Ring of Honor inductee, Pro Football Hall of Fame inductee 1971, Never had a losing season, one of two coaches to win three championships in a row (the other was Curly Lambeau in 1929-31). Also the trophy that every team in the NFL competes for is named after him.
Case Against: Like Johnny Unitas, this isn't a case that goes against him directly, but a lot of his success came in the Pre-Super Bowl era, and many of the others on this list that come after him have more success in that department.
Case For: Won the 1964 NFL Championship. All-time winningest coach in NFL history with 347 wins. Only coach to ever have a perfect season (1972). Two-time Super Bowl Champion (Super Bowl VII, Super Bowl VIII). In 33 seasons of coaching he had only one losing season (1988). He's tied with Bill Belichick for most Super Bowl appearances with six. Made it to three Super Bowls with five different quarterbacks (Johnny Unitas, Earl Morrall, Bob Griese, David Woodley, and Dan Marino). Coach of the Year in 1964, 1967, 1968, 1970, 1971, and 1972. NFL 1970s All-Decade Team. Dolphins Honor Roll Inductee. 1997 Pro Football Hall of Fame Inductee.
Case Against: He's tied with Bud Grant, Marv Levy and Dan Reeves for most Super Bowl losses with four. He couldn't win a Super Bowl with Dan Marino on hand. His 17-14 postseason record isn't as good as the records of Chuck Noll or Bill Belichick.
Case For: He took a Steelers team that had one win in 1969 and by 1972 he turned them into a dynasty. Four time Super Bowl Champion (Super Bowl IX, Super Bowl X, Super Bowl XIII, Super Bowl XIV). Along with Bill Belichick he's the only coach to win four, and he's the only coach to win back-to-back Super Bowls twice. 1989 Coach of the Year. NFL 1970s and 1980s All-Decade Team. 1993 Pro Football Hall of Fame Inductee.
Case Against: After Super Bowl XIV, Nolls' Steelers would make it to the playoffs only four more times and come away with only one win.
Case For: Third-winningest coach of all time, Second-winningest postseason coach of all time. 1966 NFL Coach of the Year. Invented the 4-3 defense. Two-time Super Bowl Champion (VI, XII). His record of 20 consecutive winning seasons still stands. The Cowboys made 12 NFC Championships in 17 years, 10 of them in a span of 13 years. Dallas Cowboys Ring of Honor Inductee. 1990 Pro Football Hall of Fame Inductee. Invented the shotgun formation. Took the Cowboys from a doormat to America's Team.
Case Against: His teams struggled late in his career and he's 2-3 in Super Bowls, with two of the losses coming against Chuck Noll's Steelers.
Case For: Only coach to win a Super Bowl with three starting quarterbacks (Doug Williams, Mark Rypien, and Joe Theismann). Invented double and triple tight end sets and trips formation. 3 time Super Bowl Champion (XVII, XXII,XXVI). 3 time Coach of the Year (1982,1983,1991). 1996 Pro Football Hall of Fame Inductee.
Case Against: His second tenure where he went 21-34.
Case For: Took the 49ers from 2-14 to Super Bowl Champions in three seasons. Has a coaching tree with more than 25 coaches and 9 Super Bowl Champions. Developed the West Coast offense. Three-time Super Bowl Champion (XVI,XIX,XXIII). Two-time Coach of The Year (1981,1984). 1980s NFL All-Decade Team. 1993 Pro Football Hall of Fame Inductee.
Case Against: He didn't have the long tenure of some of the other coaches on here and had three consecutive one-and-dones.
Case For: Two-time Super Bowl Champion (XXI, XXV). Three-time Coach of the Year (1986,1994,1996). NFL 1990's All-Decade Team. Only coach to lead four different teams to the playoffs and three to a conference title game. Had only two losing seasons, one of them during the strike shortened 1987 season. 2013 Pro Football Hall of Fame Inductee. His coaching tree boasts Bill Belichick.
Case For: Four-time Super Bowl Champion (XXXVI, XXXVIII, XXXIX and XLIX). Three-time Coach of the Year (2003, 2007 and 2010). NFL 2000's All-Decade Team. Fifth-most winningest coach and winningest postseason coach of all time.
Case Against: Lost two Super Bowls to Tom Coughlin. Wasn't particularly successful before Tom Brady. Also the Spygate and Deflategate scandals might sour the view.
Case For: Won two Super Bowls against Bill Belichick (XLII and XLVI). Best coach in Jacksonville Jaguars history.
Case Against: Outside of those Super Bowls his teams have been anywhere from first round playoff losers to awful.