The 20-year-old midfielder has attracted interest from several major European clubs after emerging as a key figure for AZ.
Smit made his senior debut during the 2023-24 season before enjoying a breakthrough campaign that established him as a regular in the first team. His performances have since prompted reported interest from Barcelona, Real Madrid, Liverpool, Chelsea and Tottenham.
AZ have now confirmed that Smit has agreed to remain at the club until the summer of 2030, extending a relationship that began when he joined their academy as a nine-year-old.
The midfielder said he was happy to commit his future to the club and continue his development in familiar surroundings.
“It feels very secure here. The trust from the club is enormous, of course. It feels very secure here and there is still a lot to learn. We basically reached an agreement quite quickly,” Smit said.
His development has been closely linked to AZ's youth system, where he progressed through the various age groups after arriving from local club De Foresters. He made his professional debut for Jong AZ shortly after turning 17 before earning his first-team opportunity a year later.
Smit has continued to establish himself at senior level, with his technical ability and composure in midfield making him an important part of the squad.
Last season, he recorded five goals and nine assists in 46 competitive appearances for AZ. He has added two assists in seven appearances so far this season, continuing to contribute as the club builds around its emerging talent.
The contract extension represents a significant commitment from both sides. For AZ, retaining a homegrown midfielder who has attracted attention from some of Europe's biggest clubs offers continuity and the chance to continue his development in Alkmaar.
For Smit, the new deal provides a platform to gain further experience and build on the progress that has taken him from the academy into the first team.
He has also earned international recognition, having represented the Netherlands at senior level once, alongside appearances for the country's youth teams.
With his future now secured through 2030, AZ will hope Smit can continue his upward trajectory and become an even more influential figure in the seasons ahead.