The announcement is the latest in a string of changes in the Gunners’ backroom staff with Arsene Wenger staging a shake-up.
Luke Hobbs, doing the job on an interim basis since Andries Jonker left for Wolfsburg earlier this year, continue until then.
Mertesacker, a 32-year-old World Cup winner, wants to have just one more season as a player before taking on responsibility for the development of youth players at Arsenal.
He said: “This is the start of an exciting new chapter for me and I am delighted that I will be able to stay part of the Arsenal family.
“This season I will remain fully focused on my job with the team and am looking forward to a successful last season on the pitch. After that, I look forward to the exciting challenge of helping produce young players good enough to play for the Arsenal first team.”
Earlier this week Mirror Football revealed Jens Lehmann is to rejoin the club for a third spell, this time as first-team coach.
Fitness coach Tony Colbert has been moved sideways while Australian Darren Burgess, has been brought in as Director of High Performance.
Legal expert Huss Fahmy has also come in to work alongside chief negotiator Dick Law.