Duane Charles "Bill" Parcells (born August 22, 1941), also known as "The Big Tuna", is an American former football coach who was a head coach in the National Football League (NFL) for 19 seasons.
He rose to prominence as the head coach of the New York Giants, whom he led to two Super Bowl titles.
Parcells later served as the head coach of the New England Patriots, New York Jets, and Dallas Cowboys.
Throughout his career, he coached teams that were in a period of decline and turned them into postseason contenders.
He is the only coach in NFL history to lead four teams to the playoffs and three teams to a conference championship game.
When Parcells became the head coach of the Giants in 1983, he took over a franchise that had qualified for the postseason only once (1981) in the past decade and had only one winning record in their last 10 seasons.
Parcells brought new success to the team and within four years, guided them to their first Super Bowl win.
His tenure with the Giants spanned eight seasons and concluded with a second championship victory in Super Bowl XXV.
After the Super Bowl win, Parcells retired as a coach in 1991.
In 1993, Parcells came out of retirement to become the head coach of the Patriots, another struggling franchise at the time.
Once again, Parcells changed the fortunes for the team and led them to an appearance in Super Bowl XXXI during his fourth season as their coach, although the game ended in defeat for the Patriots.
Amid conflicts with Patriots owner Robert Kraft, he left the franchise after their Super Bowl loss and became the head coach of the Jets for the next season.
Under Parcells, the Jets went from having only one victory in the previous season to obtaining a winning record, and they reached the 1998 AFC Championship Game in his second year with the team.
After three seasons as the Jets' head coach, Parcells retired for a second time in 1999, but came back to football in 2003 to become the head coach of the Cowboys.
He coached the Cowboys for four seasons and helped them qualify for the playoffs twice, although the team was eliminated in the first round each time.
Following the team's loss in a 2006 NFC Wild Card game, Parcells retired from coaching for good in 2007.
Since his final retirement from coaching, Parcells currently serves as an NFL analyst for ESPN and since 2014, has been an unofficial consultant for the Cleveland Browns.
He was also the Vice President of Football Operations with the Miami Dolphins, a position he held from 2008 to 2010.
In 2013, Parcells was voted into the Pro Football Hall of Fame.His life story, "Parcells: A Football Life" was co-authored by Bill Parcells and writer Nunyo Demasio, a former Washington Post reporter.
The collaboration was released by Penguin Random House in late 2014, and soon became a New York Times bestseller.