Sponheim studied agricultural science at the Norwegian Agricultural University ( now University of Environmental and Life Sciences ) in Ås. He ran beside the policy his court in Ulvik, Hordaland. The couple has three children Sponheim.
1993-2001 and again in 2005-2009, he was a Member of Parliament for the constituency of Hordaland in the Storting. In the first cabinet of Kjell Magne Bondevik (KrF ) Sponheim was from 1997 to 2000 Minister of Economy and Trade. In the government Bondevik II he served 2001-2005 as the successor of Bjarne Håkon Hanssen, the Office of the Minister of Agriculture.
Sponheim was one of the most prominent politicians in Norway and an extremely streibarer character. Fascination and criticism reflected in the dictum he possessed " an ego bigger than his party."
As Venstre top candidate in the general election in 2009 Sponheim tried to maneuver between the left and the bourgeois camp. While he publicly wanted to keep the option of a bourgeois minority government in the game, he secretly probed with Jens Stoltenberg, a center-left coalition led by the Workers' Party. According to political observers, the contradictory statements coalition caused the decline of the Liberal votes among the four percent threshold. Venstre lost an eight out of ten mandates and preserved only ever a constituency mandate in Oslo and Akershus. As a consequence Sponheim announced on 29 September 2009, his resignation from the party chairmanship. His successor Trine Skei Grande was elected on 17 April 2010.
Since 2010 Lars Sponheim Government President ( fylkesmann ) in his former constituency of Hordaland.