On May 10, 2012, Belichick was hired as a coaching assistant by the New England Patriots, where his father Bill was the head coach.[4] He served in that position for four seasons before being named safeties coach prior to the start of the 2016 season.[5] He won his first Super Bowl when the Patriots defeated the Seattle Seahawks in Super Bowl XLIX.[6]
On February 5, 2017, Belichick was part of the Patriots coaching staff that won Super Bowl LI. In the game, the Patriots defeated the Atlanta Falcons by a score of 34–28 in overtime.[7]
For the 2019 season, after long-time assistant Brian Flores left to become the new head coach of the Miami Dolphins, Belichick assumed defensive play calling duties previously held by Flores while also operating as the team's secondary coach.[8] He won his third Super Bowl title when the Patriots defeated the Los Angeles Rams in Super Bowl LIII.[9] The Patriots held the Rams to three points in the lowest scoring Super Bowl ever.[10]
On July 28, 2020, the Patriots moved Stephen from safeties to outside linebackers coach and promoted his brother Brian to safeties coach.[11]
Belichick is the son of legendary NFL head coach Bill Belichick and the grandson of Steve Belichick. His younger brother, Brian Belichick, works in the New England Patriots organization, currently serving as the team's safeties coach.[13]