Peacock, who previously worked for the Rams as Academy Director, rejoins the club as first team coach to work alongside newly appointed manager Paul Clement.
In his time at The FA, Peacock has led the Under-17s to two European Championship titles, in 2010 and 2014, and has managed over 100 games in UEFA competition, with a 69% win record.
John Peacock factfile
DOB: 27 March 1956
England U17s record:
Played 228
Won 133
Drawn 48
Lost 47
Honours: European U17s Championship winner 2010, 2014
Peacock said: “This has been one of the most difficult decisions I have had to take.
"Leaving an organisation like The FA where it has so many outstanding individuals has not been easy.
"It has been an absolute privilege to work here for two spells spanning a total of 21 years. In recent years I have been a National Coach, Head of Coaching and England U17 Head Coach, as well as Head of Elite Senior Coach Development.
"These roles have brought me in to contact with so many professional people within the organisation, coaches and of course some of the best young players in this country.
“I have had the pleasure of supporting, developing and managing the next generation of coaches and managers through their coaching qualifications.
"We have without doubt some highly motivated coaches who are keen students of the game who continually strive to improve themselves.
"In my various professional roles I have also worked closely with all our stakeholders, in our concerted desire to improve the quality of coaching and players in this country, which I sincerely think is being achieved."
He continued: “Developing so many talented young elite players through the England international youth teams programme these past 13 years has been an amazing experience.
"We have very talented players in this country and to play a small part in their development has been challenging and extremely rewarding for me personally.
"I leave The FA on a positive note having just qualified once again for the FIFA U17 World Cup in Chile in October – I wish all the players and staff every success.
“It is in respect of a further challenge which has subsequently taken me towards making this difficult decision.
"The last 25 years of my working life has been spent with The FA and Derby County FC.
"The chance to work once again at this fantastic club, which has an outstanding infrastructure and above all else highly passionate supporters and Board of Directors who have an ambition for success, meant the challenge of re-joining as first team coach was an opportunity I couldn’t decline.
Peacock and captain Ryan Ledson after winning the Euros in 2014
“Finally, it is always refreshing to see an English coach succeed.
"Furthermore it is even more difficult for this to happen abroad. In Paul Clement we have this person after his successful spells at Chelsea, Paris Saint-Germain and, of course, Real Madrid.
"I was delighted when Paul offered me this opportunity to assist him in his role as the Head Coach of Derby County. I am really looking forward to the next chapter in my coaching career.”
FA Technical Director Dan Ashworth added: “We will sorely miss John and I can only thank him for his contribution to The FA and England, both as a coach and a coach educator.
"His record speaks for itself and Derby County have a fine coach to supplement the work of Paul Clement.
"On behalf of everyone The FA I would like to wish John well – he leaves behind a great legacy through his work.”
As a player, Peacock spent seven seasons with Scunthorpe, playing more than 200 league and cup games.
