Early career

Growing up in Tyrsted, a southern suburb of Horsens, Hausner started playing football as a six-year-old for local club FC Horsens. At under-13 level he moved to Horsens fS, which became the youth academy of AC Horsens – the major professional club in the area – a year after his arrival.^[1] As a defensive midfielder, he was part of the team winning the Jutland Championship for U13-teams in his first year at the club.^[1] At under-14 level, Hausner grew into team captain, and was lauded for his leadership and aggressive playing style.^[1][3]

AGF

In November 2014, 14-year old Hausner joined AGF from AC Horsens.^[4] One and a half year later, he signed his first youth contract with the club.

In March 2017, Hausner was called up to the first team for the Danish Cup quarterfinal against his former club AC Horsens. AGF was under pressure due to the many injuries in the defence but Hausner did not make his debut in that game.^[5] Two months later, he was promoted into the first team squad permanently at the age of 17.^[6] In the following season, Hausner sat on the bench for four games in the Danish Superliga.

His official debut came on 26 September 2018 in the Danish Cup against Aarhus Fremad where he played the last 15 minutes.^[7] Hausner also got his Danish Superliga debut in March 2019 against Vendsyssel FF.

In July 2019, he signed a four-year contract extension to his contract for four years.^[8] That season, he experienced his breakthrough for the club under head coach David Nielsen, making 18 appearances – 17 as a starter – in the Superliga,^[9] as AGF finished in third place and secured medals for the first time since 1997.^[10][11]

At the same time as teammate Albert Grønbæk, Hausner signed another contract extension in mid-December 2020, valid until the end of 2025.^[12] He remained a starter in defense for most of the 2020–21 season, as AGF once again qualified for the championship round and finished in the top spots in the league table. Due to his performances, rumours of a summer move materialised.^[13] On 20 May 2021, Hausner made a mistake that led to Mikael Uhre from Brøndby IF scoring the 2–1 winner, bringing the club one game away from their first league title in 16 years.^[14][15] Afterwards, he received online threats and accusations of match fixing.^[16] Director of communication in AGF Søren Højlund Carlsen called the accusations "violent", and said that "they were derogatory terms from the ugliest side of the dictionary, which must stop", and further called for a "need to talk to each other properly".^[17][18]

IFK Göteborg

On 30 January 2023, Hausner signed with Allsvenskan club IFK Göteborg on a deal until 2026.^[19] He made his debut for the club on 5 March, starting in a 4–0 home defeat against IFK Norrköping in Svenska Cupen.^[20] He was criticised after the game by pundit Astrit Ajdarević, after failing to clear the ball which led to Norrköping's opening goal.^[21] His league debut following on 2 April, the first matchday of the season, again featuring in the starting lineup as Göteborg lost 1–0 at home to IFK Värnamo.^[22] On 27 August, he scored his first goal for Blåvitt, as well as his first professional goal, helping them to a 4–2 home victory against BK Häcken.^[23] Hausner ended the season with one goal in 25 total appearances for the club.^[9]