Kozhemyako was appointed as the representative of the Legislative Assembly of Primorsky Krai in the Federation Council in 2002.

On 16 October 2008 President Dmitry Medvedev appointed him to the Amur governorship to replace Nikolai Kolesov.

[4] President Vladimir Putin appointed Kozhemyako to the governorship of Sakhalin Oblast on 25 March 2015 to replace Alexander Khoroshavin, who was arrested and charged with accepting bribes.

[10] In February 2023, the Office of Foreign Assets Control of the United States Department of the Treasury added Kozhemyako to the Specially Designated Nationals and Blocked Persons List.

[13] In June 2023 he led a delegation to Belarus with the goal of negotiating the release of the Vladivostok-born political prisoner Sofia Sapega.