Oleg Kozhemyako was born on 17 March 1962 in Chernigovka village, Chernigovsky district, Primorye Territory.
Graduated from the Khabarovsk School of Mechanics, passed compulsory military service in the Armed Forces; graduated from the Far Eastern Institute of Soviet Trade (Pacific State Economic University) specializing in Economics.
Started working in 1981 in the sphere of production and worked his way up from a regular mechanic of 3rd class to foreman at the Primorskaya State District Power Station.
In October 1989, created Primorsky production co-operative store that transformed into Primorskoye food production association in 1992.
In 1995, was elected Deputy Chairman of the Board of Directors at OJSC Preobrazhenskaya Base of Trawler Fleet.
In 1998–2002, Chairman of the Board of Directors at OJSC Preobrazhenskaya Base of Trawler Fleet.
On 9 December 2001, elected Deputy of the 3rd Legislative Assembly of the Primorye Territory, served as a member of the Committee on Food Policy and Environmental Management.
On 27 November 2002, elected Representative to the Federation Council of the Federal Assembly of the Russian Federation from the Primorye Territory Legislative Assembly, served as a member of the Committee on Natural Resources and Environmental Protection, served on the Committee on Youth and Sport and the Committee on Information Policy.
Since October 2004, served as Advisor to Chairman of the Federation Council of the Russian Federation Sergei Mironov.
On 18 January 2005, appointed Vice-Governor of Koryaksky Autonomous Area, managed issues of the delivery of goods to the Northern territories and provision of the region with fuel.
On 9 March 2005, appointed acting Governor of Koryak Autonomous Okrug.
On 14 April 2005, approved as Governor by the Legislative Assembly of the region.
In July 2007, included into the Advisory Committee of the State Council of the Russian Federation.
In 2007–2008, worked as Aide to the Head of the Presidential Executive Office.
On 20 October 2008, approved as Governor of the Amur Region by deputies of the Legislative Assembly of the Region.
On 25 March 2015, appointed acting Governor of the Sakhalin Region by the President of the Russian Federation Vladimir Putin.
On 13 September 2015, elected by over 67% of the citizens of Sakhalin and the Kuril Islands at the direct early elections of the Governor of the Sakhalin Region.
On 21 September 2015, officially took the office of Governor of the Sakhalin Region.
Full State Counsellor of the Russian Federation of the 3rd Class. PhD in Economics.
Married with a son and a daughter.