Frank de Boer has signed a long-term contract to keep him as Ajax head coach until June 2014.
The former Holland defender succeeded Martin Jol on a caretaker basis on December 6 following the latter's resignation.
And he has now been handed the reigns on a permanent basis, with Hennie Spijkerman joining Danny Blind as his assistant.
He told the club's official website: "I'm not surprised by this appointment as the intention of both sides was there from the start. We only needed to work out some details and that happened today."
Club director Rick van der Boog added: "Frank knows the club as player and youth coach and knows exactly what is demanded."
De Boer played for the club for 11 seasons from 1988, making over 400 appearances before leaving Holland to play for Barcelona and Rangers among others.
He was assistant to Holland coach Bert van Marwijk at this summer's World Cup and has also worked with Ajax's much-vaunted youth teams since 2007.
