The loan then became a permanent deal in July 2015, after the club suffered relegation to the third tier at the end of the season.

[9][10] In January 2019, it was announced that Kiilerich would be joining Danish Superliga club AC Horsens from the 2019–20 season onward.

The team struggled to maintain a clean sheet from October 2022 to June 2023, conceding a league-high 58 goals.

Ultimately, their relegation occurred due to goal difference, narrowly missing out to Lyngby.

[13][14] On 1 September 2023, Kiilerich made his return to Hvidovre, who had secured promotion to the Superliga in the interim.