Fickell and the school reached an agreement late Friday night. An official announcement is expected later Saturday, and Cincinnati's board of trustees has a special meeting scheduled for Sunday where it will "consider the appointment, employment, promotion, demotion, or compensation of a public employee."
Fickell, 43, replaces Tommy Tuberville, who resigned after going 4-8 in his fourth season and 29-22 overall at Cincinnati. Fickell interviewed with Cincinnati athletic director Mike Bohn on Thursday.
It's not yet known whether Fickell will remain with No. 3 Ohio State for its upcoming matchup with No. 2 Clemson in the College Football Playoff semifinal at the PlayStation Fiesta Bowl.
A Columbus native and former Ohio State defensive lineman, Fickell has coached at his alma mater since 2002, serving as Buckeyes defensive coordinator in some capacity in all but one season since 2005. He also coaches Ohio State's linebackers.
Fickell was Ohio State's head coach during the 2011 season following the Memorial Day resignation of Jim Tressel amid an NCAA investigation. Ohio State went 6-7 that season and then hired Urban Meyer. Fickell interviewed for the head-coaching vacancy at Pitt before remaining with the Buckeyes as co-defensive coordinator.
Sources say Cincinnati also had targeted Jeff Brohm and P.J. Fleck for its opening. Brohm opted to leave Western Kentucky for Purdue, and Fleck didn't have interest in the Cincinnati job and likely will remain at Western Michigan, where he's expected to receive a restructured contract.
Fickell's biggest challenge will be to fix Cincinnati's issues on offense. The Bearcats' scoring offense (19.3 points per game) ranks 120th out of 128 FBS schools this season.
He is the third assistant from Ohio State's 2014 national championship team to land a head-coaching job, joining Tom Herman and Chris Ash.