Belichick's father, Steve Belichick, was considered one of the great football scouts of his time, serving as an assistant for 30 years at Vanderbilt, North Carolina, and the Naval Academy. He also wrote a book, "Football Scouting Methods."
SOURCE: Grantland
Belichick considered his father to be his one constant mentor, with his dad allowing him read through the scouting reports at age 9 if Bill had finished his homework.
SOURCE: Grantland
Belichick played football at Annapolis High School in Maryland (No. 50) and on the Wesleyan University football team in Connecticut as a tight end and center.
After graduating from Wesleyan, Belichick sent out ~250 letters looking for a coaching job before landing one as an assistant for Baltimore Colts head coach Ted Marchibroda in 1975.
SOURCE: Yahoo Sports
Billy" Belichick was 22 years old at the time and was paid $25 a week to study film and run errands. Belichick would later say about his success as a coach, "I wouldn't be here if not for Ted Marchibroda ... I learned so much from him," Belichick said. "A lot of X's and O's, but it really wasn't the X's and O's. It was a lot more about just being a football coach, being a professional coach, preparation, work ethic, dependability, what goes into having a good football team.
SOURCE: Yahoo Sports
In 1976 and 1977, Belichick moved on to the Detroit Lions where he served as a special teams assistant and as a receivers coach under Tommy Hudspeth. The Lions missed the playoffs both years.
In 1978, Belichick picked up his first defensive coaching gig, serving as a defensive assistant for the Denver Broncos. The defending AFC champs went 10-6 and made the playoffs.
It was the following year, in 1979, when Belichick got his first big break. At age 27, he was hired as an assistant by the New York Giants and new head coach Ray Perkins.
While Perkins was out after four seasons, having made the playoffs just once, Bill Parcells kept Belichick on the staff when he took over.
In his third season under Parcells, Belichick was promoted to defensive coordinator. The following year, the Giants won the Super Bowl.
On his time with the Giants: "I was just trying to establish my coaching career, be a good coach, win some games ... [the Giants are] a great organization. It is hard not to get choked up about it ... I loved it here. I loved it here."
SOURCE: NFL Network
After winning a second Super Bowl with the Giants in 1990, Belichick got his first head coaching job with the Cleveland Browns in 1991. He was 38 years old when he was hired, six years younger than any other head coach in the NFL at the time.
Belichick spoke about being a young coach at the time: "I feel like I've been coaching for 30 years, starting at 8, around the films. I've done all the jobs in an organization: typing, going to the airport to meet guys, liming the field."
SOURCE: New York Times
Belichick went 36-44 in five years with the Browns, making the playoffs once. However, after the 1995 season, Art Modell moved the Browns to Baltimore and Belichick was fired.
Belichick wasn't out of coaching long, re-joining Bill Parcells' staff in 1996 with the Patriots and then going with Parcells back to New York when he became head coach of the Jets.
That's when things got weird. After Parcells resigned following the 1999 season, Belichick was promoted to head coach. But at the introductory press conference the next day, Belichick hand-wrote a note that simply read that he was resigning as "HC of the NYJ." He then met with the media to discuss his resignation after one day.
SOURCE: SI.com
Bill Belichick spends a lot of time in the summers picking the brains of other coaches. This is a big reason why the Patriots have been successful offensively and defensively even though Belichick's background is as a defensive coach.
SOURCE: Grantland
Belichick never stops coaching, even when he is playing catch with his son Brian.
SOURCE: NFL Network
While many coaches subscribe to a particular football system, whether it is a west coast offense vs. a running attack or a 3-4 defense vs. a Tampa-2, Belichick has never limited himself to one set style, often adapting his team from year to year and week to week.
When asked about his preference for a 3-4 defense (3 linemen, 4 linebackers): "I think honestly that's something that's a media fabrication ... look, you have 11 players. You can put them in various positions. Whether you want to put it in the pregame depth chart as one thing or another I think is a little bit overrated."
SOURCE: Patriots.com