Open Rants by CoachBowlesStats

I. The Beginnings of the Bill Walsh Coaching Forest

Upon the Bengals' elimination from the postseason in the 1975 NFL season, Paul Brown retired from coaching and was forced to choose his successor. Brown's options were narrowed to two of his long-time assistants -- Bill "Tiger" Johnson, a former player who coached with passion, and Bill Walsh, an innovative coach who worked closely with Brown in developing an offense to suit quarterback Vigil Carter's strengths. Paul Brown opted for the former, a decision which would forever change the course of football history. Whereas Bill Johnson flamed out after two-and-a-half years of coaching the Bengals, Walsh's career took a very different turn. Bill Walsh left the Bengals for the Chargers in 1976, accepting an offensive coordinator position in San Diego. Walsh then spent two years as the head coach of the Stanford Cardinals before accepting the position of head coach of the San Francisco 49ers in 1979. 

Bill Walsh's 10-year tenure as the head coach of the 49ers was the most influential head-coaching-term of all time for one simple reason -- Walsh's innovation of the West Coast Offense. Walsh's offense, which emphasized the short passing game and stretching the defense horizontally, ranked top-five in the NFL in 8 of his 10 years as head coach, netting his team 3 Super Bowl victories. As a result of the 49ers' great success under Walsh, their assistant coaches became increasingly in demand for head coaching positions. In 1979, Joe Montana's rookie season, Walsh hired Sam Wyche to be his quarterbacks coach. Wyche would spend four seasons with the Niners before taking a head coaching position with the Bengals in 1984. To replace Wyche, Walsh hired Paul Hackett, who served as his quarterbacks coach from 1983 through 1985. Hackett's replacement was Mike Holmgren, who served as Walsh's quarterbacks coach from 1986 through 1988 before landing a head-coaching gig of his own with the Packers in 1992. Walsh hired George Seifert to be his defensive backs coach in 1980. Walsh promoted Seifert to defensive coordinator in 1983, and Seifert would ultimately succeed Walsh as head coach of the 49ers in 1989. Finally, Walsh hired Dennis Green to be his receivers coach in 1986 who, after a short stint in college, accepted a job as the Vikings' head coach in 1992. These five assistant coaches would each find considerable success on their own, forming the first generation of the Bill Walsh Coaching Forest. 

II. 1989 Through 2002

The fourteen years following Bill Walsh's retirement as head coach of the 49ers were characterized by dominance by West Coast disciples. In particular, George Seifert, Mike Holmgren, and Dennis Green each won over 100 games, including postseason, during this timespan. 

George Seifert took over the 49ers for Bill Walsh in 1989, hiring Mike Holmgren as his offensive coordinator. That season, the 49ers went 14-2 and won the Super Bowl on the back of MVP Joe Montana. In 1990, Seifert and Holmgren again went 14-2, and Joe Montana again won the MVP award. Upon Mike Holmgren's departure in 1992, Seifert hired ex-Raider head coach Mike Shanahan to be his offensive coordinator. After three consecutive double-digit wins seasons together, including a Super Bowl victory in the 1994 season, Shanahan took a head-coaching position of their own with the Broncos in 1995. As Seifert continued to pile up double-digit wins seasons every year from 1995 through 1998, Shanahan excelled to an even higher degree. The Broncos, led by Mike Shanahan, offensive coordinator Gary Kubiak, and quarterback John Elway capped their 1997 and 1998 seasons with Super Bowl victories. Despite John Elway's retirement, Shanahan and Kubiak still avoided losing seasons in 2000, 2001, and 2002. Meanwhile, Seifert's Niners opened the millennium hot as well, qualifying for the postseason in 2001 and 2002. 

Mike Holmgren took the Packers' head coaching job in 1992 and immediately hired Steve Mariucci to be his quarterbacks coach, Andy Reid to be his tight ends and assistant offensive line coach, and Jon Gruden to be an offensive quality control coach. The Packers went 9-7 in 1992, 1993, and 1994, before breaking through and going 11-5 in 1995, carried in part by MVP quarterback Brett Favre. This season prompted the California Golden Bears to hire Steve Mariucci as their head coach and the Eagles to hire Jon Gruden as their offensive coordinator. Nevertheless, the Packers took another leap in 1996, going 13-3, having the top-ranked scoring offense, and winning the Super Bowl. Brett Favre again won the MVP award. Under Holmgren, the Packers went 13-3 in 1997 and 11-5 in 1998 before Holmgren decided to leave and take the Seahawks' head coach job in 1999. Meanwhile, Jon Gruden became the head coach of the Oakland Raiders in 1998, immediately improving the Raiders from 4-12 to 8-8. The Raiders made the postseason in 2000 and 2001 before trading Jon Gruden to the Buccaneers. Gruden's Bucs would go on to defeat the Raiders in the Super Bowl in 2002. Moreover, Andy Reid got his own head coaching job with the Eagles in 1999. Under Reid, the Eagles made the playoffs in 2000, 2001, and 2002. 

Dennis Green took the Vikings' head coaching job in 1992, hiring Brian Billick as his tight ends coach and going 11-5 in his first year. Green established a winning culture in Minnesota, as the Vikings made the playoffs eight times from 1992 through 2000 with a variety of different quarterbacks, including a 15-1 campaign in 1998 with Pro Bowl quarterback Randall Cunningham. Brian Billick got a head coaching gig of his own with the Ravens in 1999. He immediately established a winning culture in Baltimore, capping his second season in 2000 with a Super Bowl victory, led by quarterback Trent Dilfer. 

III. Walsh's Modern Influence

Just as the 10th and 11th centuries AD were characterized by a theological split between East and West, the mid-2000s were characterized by a philosophical split between left and right of the Walsh Forest (each assistant on the tree is sorted by when they were first employed by their "parent" coach). The division between the two main philosophies shall henceforth be known as the "Gruden-Mariucci Partition" -- everyone below, left-of, and including Jon Gruden is now part of the so-called "Shanahan-Gruden Tree;" everyone below, right-of, and including Steve Mariucci is now part of the "Andy Reid Tree." Assistants such as Greg Olson, Nathaniel Hackett, and Jeremy Bates have bounced around the Shanahan-Gruden Tree without dabbling with the Andy Reid Tree. Similarly, on the right side, assistants such as Marty Mornhinweg, Mike Shula, and Darrell Bevell have moved around on the Andy Reid Tree without much contact with the Shanahan-Gruden Tree. Philosophically, the Shanahan-Gruden Tree emphasizes zone running, play action, and pre-snap shifts, whereas the Andy Reid Tree emphasizes varied personnel groupings, spread concepts, and options. 

Twelve different men in the Bill Walsh Coaching Forest are slated to be head coaches in 2019: Doug Marrone, Jon Gruden, Jay Gruden, Kyle Shanahan, Sean McVay, Matt LaFleur, and Zac Taylor from the Shanahan-Gruden Tree, and Andy Reid, Pat Shurmur, Doug Pederson, Matt Nagy, and Frank Reich from the Andy Reid Tree. LaFleur and Taylor were both part of the 2017 Los Angeles Rams team that improved tremendously under Sean McVay. Additionally, the Vikings, Broncos, Titans, Ravens, and Lions all have significant Bill Walsh ties, as well. The West Coast Offense has enjoyed a period of particular success in the past seven seasons, as each of the past seven Super Bowls has had a participant with Walsh connections. 

IV. The Future

Ten highly-important assistant coaches in the NFL today appear well-situated to continue Walsh's legacy into the 2020s and beyond.

Shanahan-Gruden Coaching Tree

Nathaniel Hackett, Packers Offensive Coordinator (Age: 39) -- Son of former Walsh assistant Paul Hackett, he served as the Jaguars' offensive coordinator under Doug Marrone from 2016 through 2018, including coordinating the league-leading rushing attack in 2017. Will serve as the Packers' offensive coordinator under Matt LaFleur in 2018.

Mike McDaniel, 49ers Run Game Coordinator (Age: 36) -- Has served as the 49ers' run game coordinator under Kyle Shanahan since 2017, overseeing promising seasons from Nick Mullens, Matt Breida, Marquise Goodwin, and Mike McGlinchey. Had previously served as an assistant on the 2011-2013 Redskins' coaching staffs, which have produced head coaches Kyle Shanahan, Sean McVay, and Matt LaFleur. 

Shane Waldron, Rams Pass Game Coordinator (Age: 39) -- Served as the Rams' tight ends coach under Sean McVay in 2017, part of an unit which improved from the 32nd-ranked scoring offense to the 1st-ranked scoring offense. Was given the title of pass game coordinator in 2018, a season which saw the Rams make their first Super Bowl appearance since the 2001 season. 

Brian Callahan, Bengals Offensive Coordinator (Age: 34) -- Son of former Raiders' head coach Bill Callahan, he will serve as the Bengals' offensive coordinator under Zac Taylor in 2018. Had previously served as the quarterbacks coach for Derek Carr in Oakland and for Matt Stafford in Detroit. 

Andy Reid Coaching Tree

Eric Bieniemy, Chiefs Offensive Coordinator (Age: 49) -- Served as the Chiefs' running backs coach under Andy Reid from 2013 through 2017, during which timespan Jamaal Charles, Spencer Ware, and Kareem Hunt all performed well. Was promoted to offensive coordinator in 2018, a season which saw Patrick Mahomes win the MVP and the Chiefs lead the league in offense. 

Darrell Bevell, Lions Offensive Coordinator (Age: 49) -- Served as the Vikings' offensive coordinator under Brad Childress from 2006 through 2010. Then served as the Seahawks' offensive coordinator from 2011 through 2017, during which timespan he developed Russell Wilson, presided over a top-five rushing attack 4 times, and won a Super Bowl. 

John DeFilippo, Jaguars Offensive Coordinator (Age: 41) -- Served as the Eagles' quarterbacks coach under Doug Pederson in 2016 and 2017, during which timespan Carson Wentz developed from a rookie to an MVP candidate and Nick Foles led the Eagles to a Super Bowl victory. Served as offensive coordinator for the Vikings in 2018, a season which saw Kirk Cousins post career highs in touchdowns and completion percentage. Will serve as the Jaguars' offensive coordinator in 2019. 

Press Taylor, Eagles Quarterbacks Coach (Age: 31) -- Brother of Bengals' head coach Zac Taylor, he served as the Eagles' assistant quarterbacks coach under Doug Pederson in 2016 and 2017, during which timespan Carson Wentz developed from a rookie to an MVP candidate and Nick Foles led the Eagles to a Super Bowl victory. Was promoted to quarterbacks coach in 2018, a season which saw Carson Wentz post career highs in completion percentage and yards per attempt. 

Mark Helfrich, Bears Offensive Coordinator (Age: 45) -- Served as the Bears' offensive coordinator under Matt Nagy in 2018, part of a unit which improved from the 29th-ranked scoring offense to the 9th-ranked scoring offense. Had previously served as Oregon's head coach from 2013 through 2016, compiling a 37-16 record. 

Nick Sirianni, Colts Offensive Coordinator (Age: 37) -- Served as the Colts' offensive coordinator under Frank Reich in 2018, part of a unit which improved from the 30th-ranked scoring offense to the 5th-ranked scoring offense. Had previously served as the Chargers' wide receivers coach in 2016 and 2017, during which timespan Keenan Allen, Tyrell Williams, and Dontrelle Inman performed well. 

V. Conclusion

I primarily used Pro Football Reference and Wikipediato put this together. 

As of the 2019 NFL offseason, the Bill Walsh Coaching Forest is unquestionably the greatest collection of offensive minds that the NFL has ever seen. The 29 coaches combine for a regular season head coaching record of 1739-1468-5 (.542), and they’ve won a combined 13 Super Bowls as head coaches. In 2018, the top-two-ranked offenses -- the Chiefs and the Rams -- both utilized West Coast Offenses inspired by Bill Walsh's Niners. 

As different slants on the West Coast Offense continue to emerge, it appears inevitable that new branches and trees of the Bill Walsh Coaching Forest will emerge as teams turn towards successful assistant coaches to fill their head coaching vacancies. As long as these coaches continue to innovate new strategies to stretch the defense and move the football, the Walsh Forest will continue to be vibrant and prosperous.