[1][2][3] Allen attended Texas A&M University and played as a safety on R. C. Slocum's "Wrecking Crew" defense.
In the 1994 and 1995 seasons, Allen started the final 21 games of his collegiate career and was part of a defensive unit that ranked in the top five in the nation.
[4] In 1996, Allen signed with the Buffalo Bills as an undrafted free agent but was cut during training camp.
Holding that position from 1996 to 1999, Allen worked mostly with the secondary while pursuing a master's degree in kinesiology from the Texas A&M College of Education.
[7][8][9] On January 24, 2012, Oakland Raiders' general manager Reggie McKenzie hired Allen as the team's 18th head coach.
[11] That offseason, the Raiders were facing salary cap problems and had traded away most of their draft picks prior to Allen's arrival, which did not allow him to establish his system with the right players.
[16] Following Sean Payton's retirement on January 25, Allen was promoted to head coach of the New Orleans Saints on February 8, 2022.
[17][18] On December 10, the NFL fined Allen $100,000 for defensive end Cameron Jordan faking an injury in the Week 13 game against the Tampa Bay Buccaneers.