Steven Spagnuolo was briefly a player personnel intern for the Washington Redskins in 1983. He moved around the NCAA and NFL Europe until rejoining the NFL in 1999 as a defensive assistant for the Philadelphia Eagles. He was promoted to defensive backs coach in 2001 and then moved to linebackers coach in 2004. Spagnuolo was hired as the defensive coordinator for the New York Giants, who won Super Bowl XLII, in 2007.
Spagnuolo was hired as the head coach for the St. Louis Rams in 2009. The Rams had the worst record in his first and last year as head coach. He finished with a 10-38 overall record. In 2012, he joined the New Orleans Saints as the defensive coordinator. The following year, he was the senior defensive assistant for the Baltimore Ravens before being promoted to secondary coach in 2014. He returned to the Giants as the defensive coordinator in 2015. He replaced Ben McAdoo as head coach on December 4th, 2017.