Barca have close ties to Netherlands, largely because of their association with the late Dutch great Johan Cruyff, a superstar player and highly successful head coach of the Catalan club and Ajax.
The Cruyff traditions have sustained, and De Jong is sure he will fit in at Barcelona because of that factor.
He said: "Netherlands and Barca have always had a good connection, and Barca and Ajax have a very similar way of playing, with the philosophy of Johan Cruyff. Ajax and Barca want to play in the same way, and that's great for me."
De Jong helped Ajax reach the 2018-19 Champions League semi-finals, earning widespread praise and catching the eye of the world's biggest clubs.
"My dream has always been to be a Barcelona player, so the decision to come here was very easy. I'm very happy and very proud," he said.
"When the president, Josep Maria Bartomeu, came to Netherlands expressly to see me, it showed that they believed in me a lot. They told me that I would be a very important player for the club.
"Everyone in the squad is a great player; Barca have the best players in the world and I will have to show that I can be part of the first XI, where I can play in any position in the midfield."
De Jong is naturally excited to have Lionel Messi as a team-mate, with the Argentinian having driven Barcelona to new heights over the last decade.
"I'm very happy to be able to play with Leo Messi, and I can't wait to get started," De Jong added, according to Barcelona's website.