Beginning his coaching career in 1987 at Texas A&M, Lewis served under his former college coach at Pittsburgh,
Jackie Sherrill. He would later spend time at
defensive coordinator for the
Pittsburgh Steelers and the
New York Giants. The 2013 season marked his third year as the secondary coach for the Atlanta Falcons. In 2015, Lewis became the defensive backs coach of the
San Francisco 49ers, but was let go once the season ended as part of a complete coaching overhaul. He was named the head coach of the
Birmingham Iron of the
Alliance of American Football on June 6, 2018. With two games remaining in the 10-week inaugural AAF season, Lewis and the Iron clinched a playoff berth, though due to the AAF's overall underfunding and ownership disputes, the playoffs were never played. Lewis then signed on as defensive backs coach for the
St. Louis BattleHawks of the
XFL, a position he held until the league folded in 2020. Following 2021 out of football, Lewis was named defensive coordinator for the
Houston Gamblers of the relaunched
USFL. Although Houston struggled in 2022 with a 3–7 record, all three levels of Lewis's defense had a player named to the
All-USFL Team; defensive back
William Likely, linebacker
Donald Payne, and Defensive Player of the Year pass rusher
Chris Odom. Lewis was officially hired by the
Arlington Renegades on September 13, 2022 Lewis served as co-defensive coordinator with Jay Hayes, both who among numerous St. Louis Battlehawks assistant coaches during the 2020 XFL season. Numerous Renegades defensive players had been coached by Lewis previously in the AAF, XFL, or USFL such as
Aaron Adeoye,
Joe Powell,
Will Hill, and
Donald Payne, as well as passer
Luis Perez, Lewis' quarterback for the Birmingham Iron, who was acquired via trade mid-season. The Renegades only won 4 games out of 10 in the regular season, although the defense was consistently praised compared to the Renegades offense. Despite a losing regular season record, the Renegades made it into the playoffs and recorded two upset victories to win the 2023 XFL championship. On February 14, 2024, Lewis was hired by
Boston College as the defensive coordinator. ==Head coaching record==