Kristoffer Vassbakk Ajer was born in Rælingen, Akershus County in Norway on 17 April 1998.[4] In his younger years he participated in athletics, handball and ice hockey before ending up playing football.
As a youth player he originally started his footballing career at Rælingen FK before joining Lillestrøm SK when he was eleven years old.[5] He was eventually picked up by IK Start in 2014, which marked the start of his professional footballing career as a result of his parents moving to the city of Kristiansand on the Southern coast of Norway.[5]
While playing professionally for IK Start, he attended Kristiansand Katedralskole Gimle (High School) where he was known as a very conscientious and diligent student receiving a total of 18 straight A's. He attributed this to his strong competitive instinct and self-discipline, as well as the support from his teachers and parents and the fact that he values having a good education outside of his footballing career.[6] Ajer originally planned enrolling at the Faculty of Medicine at the University of Oslo while simultaneously playing football professionally, but he has since put those plans on hold.[7] On the reasons why he excelled as a footballer, he attributed this to his early physical development, strength and maturity:
I feel like I've been pretty lucky in my career. I was developing physically from a very early age: When I was six years old I was two heads taller than the rest of the players on the field. After a match where we won 30–0, I accounted for 26 goals. I remember I was refused to play the next matches of the tournament if I could not prove my age. After this, my mother always had my passport with her when I was playing football matches.[8]
He is also a mentor/ambassador for the Equinor campaign for future athletes, entrepreneurs and talents in Norway called Morgendagens Helter ("Heroes of Tomorrow").[8]
Club career
Start
He made his professional debut for Start on 19 July 2014 in a 2–1 win against Bodø/Glimt.[9]
Ajer playing for Celtic in 2018
At 16 years of age, Ajer captained Start in a 1–1 draw against Lillestrøm on 7 April 2015, becoming the youngest ever footballer to captain a team in the Tippeligaen.[10] While playing for IK Start he played both as a central midfielder, but was gradually placed as a central defender.
Celtic
In early January 2016, Ajer had a one-week trial with Scottish club Celtic.[11] On 17 February 2016, he signed a four-year contract with Celtic and joined the club in June 2016 for a fee which could rise up to £650,000.[12][13] He was loaned to Kilmarnock in January 2017 and returned to his parent club to become a mainstay in central defence.[14] On 14 May 2018, Ajer penned a new four-year deal with Celtic.[15] On 30 August, Ajer scored his first goal for Celtic in a 3–0 win against FK Sūduva.[16]
On 24 October 2019, Ajer made his 100th appearance in all competitions for Celtic's first team in a Europa League match against Lazio.
Brentford
On 21 July 2021, Ajer completed a move to Premier League club Brentford on a five-year deal for an undisclosed fee.[17] He made his Premier League debut on 13 August 2021 in a 2–0 win against Arsenal. He scored his first goal for Brentford against Southampton on 7 May 2022.[18]
On 21 November 2023, Ajer signed a new deal with Brentford until the summer of 2028, with the club keeping an option to extend his contract for a further season. He scored his second goal against Burnley on 16 March 2024.[19]
International career
On 13 March 2018, Ajer received his first call-up to the Norwegian senior squad for friendly matches against Australia and Albania,[20] debuting in the former match to honour his late grandfather.[21]
^"Kristoffer Vassbakk Ajer" (in Norwegian). Football Association of Norway. Retrieved 7 October 2019.
^"Kristoffer Vassbakk Ajer". Norwegian Football Federation. Archived from the original on 24 October 2020. Retrieved 12 August 2022.
^ a bHenderson, Mark (16 June 2016). "New Celtic signing reveals his favoured position | CelticFC | First Team News". Retrieved 2 October 2021.
^Kristoffer Ajer at Soccerway. Retrieved 2 October 2021.
^ a b"Drømmen oppfylles i feil drakt". Romerikets Blad. 26 October 2014.
^AS, TV 2 (24 May 2018). "Kristoffer Ajer med 18 seksere på vitnemålet". TV 2. Retrieved 2 October 2021.{{cite web}}: CS1 maint: numeric names: authors list (link)
^"– At jeg fikk 18 seksere er mest honnør til skolen, ikke meg". TV 2. Retrieved 2 October 2021.
^ a b"Kristoffer Ajer". morgendagenshelter.no. Retrieved 2 October 2021.
^Johnsen, Sture (19 July 2014). "Start-Bodø/Glimt: 2–1 (0–0)". IK Start. Archived from the original on 23 February 2016. Retrieved 15 February 2016.
^Nash, Matthew (7 June 2015). "Tottenham and Liverpool chasing Norwegian wonderkid Kristoffer Ajer". HITC Sport. Archived from the original on 6 January 2016. Retrieved 15 February 2016.
^"Kristoffer Ajer: Celtic take Norwegian midfielder on trial". BBC. 5 January 2016. Retrieved 6 June 2020.
^"Kristoffer Ajer signs four-year deal with Celtic". www.celticfc.net. Retrieved 17 February 2016.
^"The hard bargaining that brought Kristoffer Ajer to Celtic". www.heraldscotland.com. Retrieved 3 October 2017.
^"Kilmarnock sign Celtic's Kristoffer Ajer on loan". BBC Sport. BBC. 20 January 2017. Retrieved 20 January 2017.
^"Kristoffer Ajer: Celtic defender signs new four-year contract". BBC Sport. 14 May 2018. Retrieved 15 May 2018.
^"Griffiths makes it a century of goals as Celts beat Suduva | CelticFC | Match Report". 12 September 2019. Archived from the original on 12 September 2019. Retrieved 2 October 2021.
^"Brentford complete signing of Kristoffer Ajer from Celtic". www.brentfordfc.com. Retrieved 21 July 2021.
^"Brentford hammer Southampton to leave Ralph Hasenhuttl facing fans' fury". www.independent.co.uk. Retrieved 20 August 2023.
^"Ajer signs new Brentford contract". Brentford F.C. 21 November 2023. Retrieved 23 November 2023.
^Madsen, Christer (13 March 2016). "Her er troppen til kampene mot Australia og Albania". Norwegian Football Federation (in Norwegian). Retrieved 16 March 2016.
^Bratland, Tore Ulrik (23 March 2018). "Holdt avtale med død bestefar i debuten". Dagbladet (in Norwegian). Retrieved 24 March 2018.