Having previously played for AB, Brøndby and Randers at youth level,[3][4] Rajović signed for B.93 in September 2018 following a trial spell at the club.[5] He transferred to HB Køge on a contract until the end of the season in January 2019,[6] but he was released when his contract expired at the end of the season,[7] having made a single league appearance for the club.[8] He joined Roskilde in summer 2019 and agreed a one-year contract with the club in September 2019.[9][10]
Næstved and Kalmar FF
Rajović signed for Næstved in January 2021.[11][12] Having scored 12 goals in his opening 17 matches of the 2021–22 season, he signed a contract extension with the club in October 2021.[13] During the 2021–22 season, he scored 18 goals in 27 games as Næstved were promoted from the Danish 2nd Division as champions,[14] and was given the club's Player of the Year award for the season.[15] In December 2022, it was rumoured that there was transfer interest in Rajović from multiple clubs in the Danish Superliga and Allsvenskan, including IFK Göteborg.[14][16] Having amassed 30 goals in 58 games for Næstved,[17] Rajović signed for Allsvenskan club Kalmar FF on a three-and-a-half-year deal on 9 December 2022.[17][18] The fee received for Rajović was a new club record for Næstved according to their sporting director Peter Dinesen.[17] His first four appearances for Kalmar came in the Svenska Cupen, in which he scored five goals.[19]
Watford
On 25 August 2023, Rajović signed for EFL Championship club Watford on a five-year contract for an undisclosed fee, reported to be around £1 million.[20][21] He made his debut as a substitute in a 1–0 Championship defeat to Blackburn Rovers on 27 August,[22] and scored a brace on his first start the following week as Watford drew 3–3 away to Coventry City.[23] On 11 November 2023, Rajović scored the first two goals in a 5-0 thrashing at home to Rotherham, making the club six games undefeated.[24] Despite Rajović starting only 17 of his 43 appearances for the 2023-24 season, he finished as the top goalscorer with 11 goals across all competitions.[25]
On 2 September 2024, Rajović returned to former club Brøndby on loan for the rest of the 2024–25 season.[26]