[3] Prior to signing, he had been diagnosed with Bekhterev's disease, a type of arthritis mainly affecting his back, but medication allowed him to play professionally.

On 24 January, he made his Gent debut against Royal Antwerp in the First Division A as a substitute in a 1–1 draw away, playing the last 45 minutes in place of Nana Asare.

On 27 August 2019, Rosted moved to Denmark to join Superliga club Brøndby on a four-year deal for an undisclosed fee,[5][6] reported to be around €300,000.

[8] Rosted soon found himself as a regular starter in the first team, establishing a partnership in central defense with fellow summer signing, Andreas Maxsø.

[15] Rosted then scored again on 2 October in a 2–1 away win over Randers FC, a 14th minute header after a corner kick provided from Jesper Lindstrøm,[16] as he was voted Man of the Match by fans afterwards.

[22] In 2017, he was called up to the Norway national team for the first time in his career, as a replacement for injured Tore Reginiussen before the friendly match against Sweden on 13 June.