At Ajax he established himself as one of the best young midfielders in Europe, after winning a domestic double and reaching the Champions League semi-finals.

[8] Frenkie de Jong started playing football at six years old when his father enrolled him at the local amateur club ASV Arkel.

Primarily he featured as a center-back, in a back four, alongside national teammate Matthijs de Ligt due to the departure of Davinson Sanchez.

De Jong made two substitute appearances in the 2017–18 Champions League qualification, as Ajax lost on away goals against Nice (3–3) in the third qualifying round.

De Jong was the Eredivisie player of the month in December (2018) and February (2019)—in which he completed 354 of 390 passes and made 53 ball recoveries.

Later that month he received praise from Rafael Van Der Vaart, who said De Jong was among the best players in Europe with the ball at his feet.

It is unclear whether during or prior to the beginning of the campaign he rejected an offer from Tottenham Hotspur, saying the "moment wasn't right," and wanted to play a full season in his preferred position at Ajax.

[22][23] On 23 January 2019, La Liga club Barcelona announced the signing of de Jong on a five-year contract, effective from 1 July 2019, for an initial fee worth €75 million.

[26] He played a crucial role in the 2021 Copa del Rey final, a 4–0 win over Athletic Bilbao, scoring in the 63rd minute and assisting two further goals.

[32] In June 2019, De Jong was included in the Netherlands' squad for 2019 UEFA Nations League Finals, where he was named as Young Player of the Tournament as the Oranje finished as runner-up to hosts Portugal.

[33] The same year in September, De Jong scored his first senior international goal in the Netherlands' 4–2 victory against Germany in UEFA Euro 2020 qualifying.

On 29 November, he scored his first World Cup goal in a 2–0 win over tournament host Qatar in the team's final group match.

[36] On 9 December, he played the full 120 minutes as the Netherlands lost in a penalty shootout to eventual winners Argentina at the quarter-final stage.

[37] In June 2023, De Jong was part of the Netherlands' squad for the 2023 UEFA Nations League Finals, where he played the full match against both Croatia in the semi-final and Italy in the third place play-off.

[38][39] De Jong was named in the Netherlands' squad for UEFA Euro 2024,[40] but had to withdraw due to an ankle injury.

De Jong's vision has been praised alongside his ability to dribble in narrow spaces, control over possession, and decisive passing.

A natural dribbler, De Jong has the highest dribbling success of all players to participate in all competitions, during his last season with Ajax.

His close control, accuracy, work rate, and movement has drawn comparisons with Andrés Iniesta and Johan Cruyff.