During a 5–1 win over AGF Aarhus on 10 August 2013, Ankersen scored a sensational goal reminiscent of Marco van Basten's strike in the final of Euro 88.

[6] In January 2014 he was signed by RB Salzburg after impressing a against them in the group stages of the Europa league, and was praised for his ability to play on either defensive flank.

[11] On transfer deadline day, 2 September 2019, Ankersen joined Italian Serie A club Genoa on a contract until June 2021 with an option for a further year.

[14] On 1 October 2020, Ankersen scored a highly bizarre own goal against Croatian club HNK Rijeka in the 2020-21 UEFA Europa League play-off round.

On 14 August 2013, he made his international debut in a 3–2 loss to Poland, coming on as a substitute for Nicolai Boilesen at half-time.

Ankersen scored his first goal ever in Denmark national team colours on 11 November 2016 in a 2018 FIFA World Cup qualification match against Kazakhstan.