Denswil began his footballing career with local amateur side Hellas Sport in Zaandam, before being recruited to join the youth ranks of Ajax in 2001.

[citation needed] Denswil was promoted to the first team squad and was given the number 34 shirt by manager Frank de Boer in the 2012–13 season.

On 18 September 2013, Denswil made his continental debut for the Ajax during the group stage of the 2013–14 UEFA Champions League campaign in the 4–0 away loss to Barcelona, in which he formed a central defensive partnership with Niklas Moisander.

[6] Following the match against AC Milan, it was announced on 5 October 2013, that Denswil had been included in the official UEFA Champions League Team of the Week, finding himself mentioned amongst the likes of Mesut Özil, Arjen Robben as well as former Ajax players Gregory van der Wiel and Zlatan Ibrahimović.

He made a total of six appearances in 2010 UEFA European Under-17 Championship campaign and also competed in the La Manga Cup in Murcia, Spain.

The intensity of his practice has slowed down immensely in order to avoid unnecessary injuries as he progressed through the youth ranks of Ajax.

His shared passion of both football and martial arts were revealed in a Voetbal International report where the magazine took a closer look at Denswil.

[22] Although the photograph was removed from the site the same day, the picture appeared on several websites shortly thereafter, eventually making headlines in the Netherlands.