ESPN first reported Thursday night O’Brien will be the next offensive coordinator for the Buckeyes.
The team’s announcement confirmed he will be quarterbacks coach as well.
“He is an excellent and experienced offensive coach who has run NFL and Power 5 programs and developed some truly elite players throughout his career,” Day said. “He’ll be an excellent teacher and recruiter for us, and he absolutely strengthens our staff.”
O’Brien is a 34-year coaching veteran who most notably spent many years as a New England Patriots assistant for Bill Belichick and was the head coach of the Houston Texans for seven seasons.
He also spent two seasons as head coach at Penn State, where he won national and conference coach of the year honors, and two seasons as offensive coordinator at Alabama, where he mentored 2021 Heisman Trophy winner Bryce Young.
Hiring O’Brien is expected to free Day, who like O’Brien is an offensive guru originally from New England, to concentrate more on the day-to-day tasks of running the program during the week and managing the game on Saturdays.
Day considered relinquishing play calling last season but ultimately did not after offensive coordinator Kevin Wilson left to become head coach at Tulsa.
While receivers coach and recruiting ace Brian Hartline will retain the title of co-offensive coordinator he received along with a pay raise last year, O’Brien is expected to become the team’s play caller.
Corey Dennis, the team’s quarterbacks coach the past four seasons, will remain part of the program in a role to be determined.
Since losing to Michigan to close out an 11-1 regular season in November, Ohio State has lost starting quarterback Kyle McCord to the transfer portal, replaced him with second-team All-Big 12 pick Will Howard of Kansas State and retained more than a dozen players who could have entered the NFL Draft.
Day also fired special teams coordinator Parker Fleming and chose not to renew the contract of safeties coach Perry Eliano, who has been replaced by Matt Guerrieri.
The Buckeyes also added All-SEC running back Quinshon Judkins from Mississippi and Alabama starting center Seth McLaughlin via the transfer portal in hopes of loading up for a run at defending national champion Michigan, the Big Ten title and the new 12-team College Football Playoff.
They will do so under the leadership of a new director of athletics, Ross Bjork, who was introduced this week and will take over July 1.