De Jong was born in Uitgeest, North Holland, where he started playing football for FC Uitgeest, before joining AZ's youth academy in 2016.[2] In January 2019, at the age of 15, De Jong joined AZ's first team during their winter training camp, where he made his unofficial debut in a friendly against Fenerbahçe.[2][3]
On 28 July 2022, De Jong made his first-team debut for AZ, coming on as a substitute in the 75th minute of a UEFA Europa Conference League second-round match against Tuzla City. He scored his first goal six minutes later, helping his side to a 4–0 victory.[6]
Cambuur
On 20 June 2023, De Jong signed a three-year contract with newly relegated Eerste Divisie club Cambuur.[7] He made his competitive debut for the club on 11 August, the first matchday of the season, starting in a 2–2 home draw against Emmen.[8] On 6 October, he scored his first goal for Cambuur in a 5–2 away league loss to Dordrecht.[9] De Jong was a key member of the Cambuur team in 2023–24, scoring six goals in 41 appearances.[1] Despite his contributions, the team finished in a disappointing 13th place in the league, although they did reach the semi-finals of the KNVB Cup.[10][11]