The Championship club parted ways with their former manager Paul Trollope
Neil Warnock is back in management after his spell with Rotherham earlier this year, signing a deal to become the new manager at Cardiff City.
The 67-year-old replaces Paul Trollope who was sacked on Tuesday after a disappointing start to the season. Cardiff have lost six of their last seven games and picked up just eight points from 11 games in the Championship.
Warnock was offered a long-term contract by Rotherham in the summer but turned it down after failing to agree terms with the club.
Kevin Blackwell and Ronnie Jepson will join Warnock as assistant manager and first team coach respectively.
The ex-Leeds United, Sheffield United and Crystal Palace manager led Rotherham to safety and now looks to improve on Cardiff's record, with the Welsh side having won only two of their 12 games this season.