Harlequins head coach John Kingston will take over as director of rugby when Conor O'Shea leaves the club at the end of the season.
Former England assistant coach Graham Rowntree has been appointed as forwards coach, while number eight Nick Easter will become defence coach.
Meanwhile, backs coach Mark Mapletoft will succeed Kingston as head coach.
"Taking the role of director of rugby is an exciting and well-timed new challenge for me," Kingston said.
He has been on the coaching staff at Harlequins since 2001, having previously had stints at Richmond and Irish side Galwegians.
Rowntree was England forwards coach under Stuart Lancaster, but left the national set-up in December when Eddie Jones was appointed as head coach.
The 45-year-old former Leicester prop won 54 caps for England and also appeared three times for the British & Irish Lions during his playing career.
"I've had an enforced step back from the game, and it's been good to spend time with the family," Rowntree told BBC Radio 5 live.
"I was delighted we won the Six Nations, but this is the start of a new adventure. I'm determined to grasp this opportunity. I'm ready for it."
Quins say the appointment of Kingston as director of rugby came following "a rigorous and wide-ranging selection process".
Chief executive David Ellis told the club website: "We were very clear that we needed somebody who would help drive us onto the next level,"
"John's passion for the club and our style of play will stand us in good stead, and convinced us he is the right man for the job."
Ex-England international Easter will primarily be a coach next season, but the 37-year-old will retain a playing contract.
O'Shea, who has won the Premiership title, the Amlin Challenge Cup and the LV= Cup during his six years as Quins boss, will leave The Stoop to take charge of Italy's national team this summer.
The Irishman could add a second European title before his departure, with Harlequins to face Montpellier in the final of the European Challenge Cup on 13 May.
In a further change to the backroom set-up, Tony Diprose will become academy and global development director.