Huff, 37, is regarded as one of the top recruiters in college football, and he also helped develop running backs Saquon Barkley at Penn State and Najee Harris at Alabama. Huff has never been a head coach at the college level.
Huff, a native of Denton, Maryland, becomes the 12th Black head coach in the FBS and the first hired this offseason. There were 14 in the FBS this past season, but three were fired: Arizona's Kevin Sumlin, Illinois' Lovie Smith and Vanderbilt's Derek Mason.
This past season, Huff helped the Crimson Tide finish 13-0 and win their sixth national championship under coach Nick Saban. Huff is the second Alabama assistant coach to leave for a head-coaching job; offensive coordinator Steve Sarkisian was hired as Texas' head coach.
In the past 14 years, FBS schools have hired 13 of Saban's assistants as head coaches. Former Tennessee coach Butch Jones, an off-field assistant to Saban the past three seasons, also was hired as Arkansas State's new head coach.
Sarkisian also is hiring Alabama offensive line coach Kyle Flood and special teams/tight ends coach Jeff Banks.
Huff previously worked at Penn State, Western Michigan, Vanderbilt and Maryland and for one season with the Buffalo Bills.
He replaces longtime Thundering Herd coach Doc Holliday, who was let go earlier this month after 11 seasons with the program.
Holliday went 85-54 at Marshall (55-30 in league play) with a Conference USA title in 2014 and three division championships. This past season, he guided the Herd to a 7-3 record and earned Conference USA Coach of the Year honors for the second time.
Marshall defensive coordinator Brad Lambert and Louisville offensive coordinator/offensive line coach Dwayne Ledford also were considered for the position.