Gailey, 67, is coming out of retirement for the job.
He last coached with the New York Jets in 2016. Gailey had a previous tenure as Dolphins offensive coordinator in 2000 and 2001. He also interviewed for the Dolphins' head coach vacancy in 2007. Gailey owns a 34-46 record as a head coach. He was 18-14 in two seasons with the Dallas Cowboys. He posted a 16-32 mark as Buffalo Bills coach from 2010 through 2012.
Gailey began his coaching career as a graduate assistant at Florida in 1974. He went on to coach defensive backs at Troy State and Air Force, before becoming the defensive coordinator at Air Force. Gailey was hired as Troy State head coach in 1983, before moving to the NFL in 1985 as the Denver Broncos special teams/tight ends coach.
He worked as an NFL positions coach until being promoted to offensive coordinator in 1989. Gailey also worked with the Pittsburgh Steelers, Kansas City Chiefs and coached at Georgia Tech and Samford, in addition to his stops in Buffalo, Miami and Dallas.
He has coached offensives into the top-10 in yards and points in three of his nine seasons as an offensive coordinator in the NFL, including the 2008 season with the Dolphins, who ranked eighth in points scored. The 1997 Steelers owned the No. 1 rushing offense in the NFL, while the 1996 Steelers ranked second in rushing, under Gailey.
Gailey also coached current Dolphins quarterback Ryan Fitzpatrick while serving as Jets offensive coordinator and Bills coach. Fitzpatrick is under contract with the Dolphins through the 2020 season.