Marcel Keizer began his coaching career with Argon in 2007.
"We had some very positive talks and I feel the club believes in me", Keizer told the club's official website. I had set myself up to get a good result in the Jupiler League next season with Jong Ajax, but in football, it may suddenly be different.
Keizer, who is the nephew of club legend Piet, up until now was the club's reserve team manager and enjoyed a productive first season in charge.
"I can't wait to get back on the field - the goal is to build on what we did last season and make this an fantastic year in which we go for trophies".
"It's appropriate for Ajax to look internally for a replacement, in the past many coaches have been appointed from within their own club".
"He knows the players, the organisation and supports the club's philosophy", added Van der Sar, one of the most-capped Dutch national players who also took the field for Ajax, Juventus and Manchester United.
'Moreover, he showed last season with a clear style of play and performed excellently'.
Keizer, who has also managed the likes of SC Cambuur and FC Emmen, admits he is delighted to have been given the opportunity to take charge of Ajax and he is looking forward to hitting the ground running at the Amsterdam Arena.