He was previously affiliated with the Conservative Party (Bokmål: Høyre; Nynorsk: Høgre) having applied for a position as political advisor on foreign affairs for Høyre.[3] He was offered the job but subsequently turned it down.[3] In 1989, Støre became special adviser in the Prime Minister's office of Gro Harlem Brundtland. .[3] He formally became a member of the Labour Party in 1995.