In 2003, the Kristiansand Chamber Orchestra and the Armed Forces Band of Southern Norway (which had its roots back to 1818) merged to form the present KSO.

During the chief conductorship of Rolf Gupta (2006–2012), the KSO took up its current residence at the Kilden Performing Arts Centre, in January 2012.

[2] In November 2022, the KSO announced that Stutzmann is to stand down as its chief conductor at the close of the 2022-2023 season.

In April 2021, the KSO announced the appointment of Tabita Berglund as its next principal guest conductor, effective 1 August 2021, with an initial contract of three seasons.

[4] In November 2022, the KSO announced the appointment of Rachlin as its next chief conductor, effective with the 2023-2024 season.