Ekkelenkamp made his professional debut in the Eerste Divisie for Jong Ajax on 9 April 2018 in a game against FC Den Bosch.[2] His Eredivisie debut for Ajax followed on 19 April 2018 in the game against VVV-Venlo.[3] On 10 April 2019, Ekkelenkamp made his UEFA Champions League debut, coming on in the 71st minute for Lasse Schöne in the quarter-final match against Juventus at the Johan Cruyff Arena.[4] The match ended in a 1–1 draw, with Ekkelenkamp receiving cult-status in the Netherlands and the nickname 'Ronaldo-gooier' (English: Ronaldo thrower) after he committed a professional foul against Cristiano Ronaldo in the closing minutes of the match.[5][6] Ajax later went on to defeat Juventus 2–1 in the return leg, making their first semi-final appearance in the tournament since 1997.[7]
Hertha BSC
Ekkelenkamp joined Bundesliga side Hertha BSC on 27 August 2021.[8] He made his debut on 17 September 2021, in a league game against SpVgg Greuther Fürth; he scored just one minute after being substituted in for Kevin-Prince Boateng, tying the score as the match ended in a 2–1 win for Hertha.[9]