Jonas Mortensen

In 2012, Mortensen joined Esbjerg fB from Varde IF at the age of 13. In December 2016, Mortensen signed a three-year youth contract with the club. Already at the age of 16, Mortensen was a starter for the U19 squad. Mortensen made his competitive debut for Esbjerg on 27 February 2019 against OB, playing 98 minutes of the Danish Cup quarter-final, which Esbjerg lost 5–4 after penalties. He made his league debut the following month, coming off the bench for Carlo Holse deep into injury time in a 2–1 victory against Vejle in the Danish Superliga. Ahead of the 2019–20 pre-season, Mortensen was permanently promoted into the first team squad. Mortensen left the club at the end of the season. A month after the club announced Mortensen's departure, it emerged that the parties had signed a new agreement until June 2024. In June 2024, Mortensen extended further until June 2027.

Club

As of match played 19 September 2026

Mortensen made his debut for Denmark under-16s on 21 May 2017, coming on as a substitute in a 1–1 UEFA Development Tournament draw against Kosovo. He made his first appearance at under-17 level in January 2018, playing in a 3–2 friendly win against Cyprus U17. He would go on to make three total appearances for the U17 team. On 13 January 2019, Mortensen made his debut for the under-19 team in a 1–1 friendly draw against Israel U19, playing the second half instead of Japhet Sery Larsen. He would go on to make 10 total appearances for the under-19 team.