Ajax have appointed Frank de Boer as permanent coach after the 40-year-old former Ajax player was in charge as caretaker since Dec. 6.

Boer, taking the helm after former coach Martin Jol resigned due to poor results, signed a new three-and-a-half year contract until 2014.

"We have a lot of confidence in Frank", general director Rik van den Boog said on the Ajax website. "Unlike his predecessors, who also had different responsibilities, he will only focus on the first team. The philosophy of the club is the philosophy of Frank de Boer."

Danny Blind will stay on as assistant until the end of this season and Hennie Spijkerman, who was technical director at Ajax Cape Town, was added to the staff as well. Dennis Bergkamp and Fred Grim will take over De Boer's former job as coach of Ajax Under 18.

Former Dutch international De Boer will quit his position as assistant coach of the Dutch national team in order to focus fully on Ajax. After he took over Ajax beat AC Milan 2-0 in the Champions League, Vitesse 1-0 in the Dutch league and won 1-0 against AZ Alkmaar in the Dutch Cup.

"I am very proud", De Boer said. "I believe I have always stayed a real Ajax person. Even when I was abroad I always kept on following the club. Ajax is the most important. I want to continue the way we work now, with good football. Results are also very important, that's part of being a top club."