[4] Despite aggregating little over half an hour of football that season, he played the three games necessary to gain a 2009 Tippeligaen medal at the age of just 17 years.

[11] His excellent season, in which he helped Rosenborg to an unbeaten league title, was rewarded with numerous awards including NISO Young Male Player of the Year[12] and Statoil's Talent Prize 2010.

[13] Don Balón named Henriksen on their list of the 100 best young players in the world in 2010, where he joined the likes of compatriot Harmeet Singh, Mario Götze, Eden Hazard, Neymar and Theo Walcott.

[14] With the sale of Anthony Annan to Schalke before the start of the 2011 season, Henriksen was asked to play a more defensive role beside the similarly attack-minded Per Ciljan Skjelbred.

[15] After three games, in which Rosenborg conceded ten goals, Jan Jönsson aborted plans on making Henriksen a defensive midfielder and brought in Fredrik Winsnes to play alongside him.

"[17] On 21 September of that year, the Daily Mirror reported that Aston Villa were interested in Henriksen whilst Napoli had also been known to have scouted him.

[18] Henriksen furthered speculation linking him abroad in a November interview with Aftenposten, "I want to try and show that I am good enough to play elsewhere than in Norway.

"[19] Late on 27 January 2012, Henriksen left Rosenborg's training camp in Benidorm for Belgium to complete a €2 million move to Club Brugge.

[20] The next day, however, Henriksen confirmed on his personal Twitter account that he had turned down a move to Club Brugge by stating, "Congratulations boys for the win.

In March 2012 he played in the league opener against SK Brann and made a further 17 out of 19 appearances, scoring one goal, until he was sold to Dutch club AZ Alkmaar in the region of €2 million.

On 31 August 2012, Henriksen left Rosenborg for a fee of around €2 million to AZ Alkmaar and signed a five-year contract with the club.

Henriksen was named as AZ player of the year this season beating top scorer Jozy Altidore and young sensation Adam Maher.

[24] On his Hull debut he assisted the first goal and scored a late winner in a 2–1 EFL Cup win over Stoke City on 21 September 2016.