Kristoffer Vassbakk Ajer (born 17 April 1998) is a Norwegian professional footballer who plays as centre-back or right-back for Premier League club Brentford and the Norway national team.
Ajer has previously played for Start in the Tippeligaen and Celtic in the Scottish Premiership, where he also had a loan spell with Kilmarnock.
Kristoffer Vassbakk Ajer was born in Rælingen, Akershus County in Norway on 17 April 1998.
In his younger years he was doing 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.
2014
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.
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.
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.
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."
He is also a mentor/ambassador for the Equinor campaign for future athletes, entrepreneurs and talents in Norway called Morgendagens Helter ("Heroes of Tomorrow").
He made his professional debut for Start on 19 July 2014 in a 2–1 win against Bodø/Glimt.
2015
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.
While playing for IK Start he played both as a central midfielder, but was gradually placed as a central defender.
2016
In early January 2016, Ajer had a one-week trial with Scottish club Celtic.
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.
2017
He was loaned to Kilmarnock in January 2017 and returned to his parent club to become a mainstay in central defence.
2018
On 14 May 2018, Ajer penned a new four-year deal with Celtic.
On 30 August, Ajer scored his first goal for Celtic in a 3–0 win against FK Sūduva.
On 13 March 2018, he was called up for the first time in the senior national team, ahead of the friendly matches against Australia and Albania, scheduled for the following 23 and 26 March respectively.
He made his debut on 23 March, in a 4–1 victory over the Australia national team.
Celtic
Brentford B
Individual
2019
On 24 October 2019, Ajer made his 100th appearance in all competitions for Celtic's first team in a Europa League match against Lazio.
On 21 July 2021, Ajer completed a move to Premier League club Brentford on a five-year deal for an undisclosed fee.
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.
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.
