In a statement the club said Van der Sar, who began his playing career with Ajax and ended it after six years at Manchester United, had joined the board along with Michael Kinsbergen who will be managing director.
"Van der Sar had a fantastic career and also has natural leadership and therefore the potential to be our managing director in the future," Ajax CEO Hans Weijers said in the statement.
"Kinsbergen will lead the board and organisation in the coming years and also guide Van der Sar in his further development."
Van der Sar retired in 2011 after a glittering career that brought two Champions League and eight domestic titles.
A number of former players have returned to Ajax in a variety of roles since a major shake-up at the club in 2011.
Frank de Boer is currently the first team manager while Marc Overmars is director of football. Dennis Bergkamp and Wim Jonk are both part of the club's coaching set-up.