Born in Horten, Gjengaar began his career with his home-town team Ørn Horten. While with Ørn Horten, Gjengaar made 15 appearances and scored 1 goal in the Norwegian Third Division. Gjengaar was the youngest player to debut with the first team of Ørn Horten, making his debut on 7 May 2019 against Vålerenga 2 at the age of 15 years and 68 days.[1] He joined Odd during July 2020, where he continued his training. Gjengaar played in the Norwegian Second Division for Odd 2, making 51 appearances and scoring 3 goals.
Odds BK
On 25 February 25, 2022, Gjengaar signed his first professional contract with Odd.[2]
Gjengaar made his first appearance with the Odds BK first team on 19 May 2022, in a Norwegian Cup match against Hei IL. He came on in place of Gilli Rólantsson as his team won 6-1.[3]
On 10 September 2022, Gjengaar started his first match in the top flight Eliteserien, scoring his first two goals as a professional in a 1-3 victory against Sandefjord Fotball.[4] His performance was praised after the match by his coach, Pål Arne Johansen, who cited that Gjengaar had great potential.[5] On 2 October 2022, Gjengaar opened the scoring for Odd in a 2-2 draw against Haugesund.[6] On 22 October 2022, Gjengaar continued his goal scoring run, opening the scoring for Odd in a 2-1 victory against Vålerenga.[7] The following match day, 30 October 2022, Gjengaar scored his fifth goal of the season in a 0-2 victory against Lillestrøm.[8]
For his second season with the first team, Gjengaar became a regular in the starting eleven for Odd. On 6 August 2023, he scored his first goal of the season in a 4-0 victory against Stabæk.[9] On 27 August 2023, Gjengaar opened the scoring for Odd in a 2-2 draw against Vålerenga[10]
New York Red Bulls
On 16 February 2024, it was announced that Gjengaar was transferred to Major League Soccer side New York Red Bulls for an undisclosed transfer fee, signing a four-year contract.[11] On 22 June 2024 Gjengaar scored his first goal for New York in a 3-0 victory over Toronto FC.[12]
International career
Gjengaar has played in various Norwegian junior national teams, including the Norway under-20 team. With the Under-19, he took part, among other things, in the U19 UEFA Euro Championship Qualifiers.[citation needed]