When Selnæs joined Rosenborg in 2009, he was earmarked for his accurate left foot and good knowledge of the game, which allowed him to develop as a defensive midfielder.

[2] In 2011, he was heavily involved in the Rosenborg under-19 side that won the national championship[4] and gained third place in their NextGen Series group.

"[15] Selnæs was a regular in Rosenborg's midfield during the first half of the 2012 season, but lost his place in the starting line-up due to an injury.

After his recovery, Rosenborg had bought Tarik Elyounoussi, Cristian Gamboa and Jaime Alas and Selnæs' chances were limited.

[21] Selnæs is a big fan of Norwegian soap opera Hotel Cæsar, and in an interview with Adresseavisen in March 2012 he stated that he would love to play a role in the show.