Paul Heckingbottom has been appointed Leeds head coach on a one-and-a-half year deal one week after signing a new contract at Barnsley.
The 40-year-old signed a 12-month rolling contract with the Tykes but emerged as the top target within the Leeds hierarchy to succeed Thomas Christiansen, who was sacked on Sunday, at Elland Road.
Heckingbottom, who had been in charge at Oakwell since Lee Johnson's departure to Bristol City in February 2016, will begin his tenure with a meeting against Yorkshire rivals Sheffield United at Bramall Lane on Saturday, live on Sky Sports Football.
A Leeds statement announcing the appointment said: "Leeds United are delighted to confirm the appointment of Paul Heckingbottom as the new head coach of the club."
He will be joined by his backroom team of Jamie Clapham (first-team coach), Nathan Winder (head of sports science) and Alex Bailey (first team performance analyst) who will also all leave Oakwell immediately.
Heckingbottom could take training later in the day as the club has pushed back Tuesday's training session after the players had Monday off.
Christiansen was given his marching orders after Leeds suffered a 4-1 thrashing at home to Neil Warnock's Cardiff on Saturday.
Leeds are without a league victory since Boxing Day at Burton and after a strong start to the season lie seven points off the play-off spots in 10th place.
The former Bradford and Norwich defender gained promotion with Barnsley from League One and won the EFL Trophy as caretaker boss before a 14th-place finish in the Championship last season.
"Barnsley Football Club are thoroughly disappointed to announce that Paul Heckingbottom has joined Leeds United," read a Barnsley club statement.
Barnsley chief executive Gauthier Ganaye said: "Yes, it was unexpected. Yes, it has come during an already complicated period.
"Yes, it will make things more difficult short term, but our club is full of resources and it is certainly not dependent on one man alone.
"I'm asking everyone from the players, employees and our loyal fans to come together as we have an important game on Saturday."
Paul Harsley will take caretaker charge at Oakwell following Heckingbottom's departure as Barnsley seek to appoint a replacement.