Dubyna graduated from Kamianske Industrial Institute with a bachelor's degree in Steelmaking in 1982 and from 1985 to 1986 he was a lecturer at the Kamianske polytechnic school. In 1986-1998, Dubyna worked for the Kamianske metallurgical complex and on 1998-1999 at the Alchevsk metallurgical complex. From 1999 to 2001 he worked as the Director General of Kryvorizhstalsteel company. In 2001, Oleh Dubyna became the Energy Minister and a Vice Prime Minister in Viktor Yushchenko's government, succeeding at this post Yulia Tymoshenko. After resignation of Viktor Yushchenko, Oleh Dubyna served as the first Vice Prime Minister in the Kinakh Government. From December 2002 until September 2003 he was an adviser of President Leonid Kuchma. On 15 September 2003 Oleh Dubyna was appointed the First Deputy Secretary of the National Security and Defense Council of Ukraine. On 18 June 2004 he was relieved and appointed the president of the national energy holding company, which was being established at the time. From June 2005 to December 2007 Oleh Dubyna worked as the CEO of the. On 24 December 2007 Dubyna was appointed the head of Naftogaz by Prime Minister Yulia Tymoshenko. On 31 December 2009 at the height of the 2009 Russia–Ukraine gas dispute Yulia Tymoshenko allegedly forced Dubyna to sign the controversial gas contract under threat of being dismissed. During the same day he also said that "Ukraine could have lived on its underground storage gas through late February without buying gas from Russia, trying to convince Kremlin to reduce the price". Later on, Dubyna as a representative of Naftogaz was charged with abuse of office for signing pact with Gazprom. He resigned from this post in March 2010 after the presidential elections and the change of the Ukrainian Government. After Dubyna's resignation Prime Minister Mykola Azarov accused him of exceeding his authority during the signing of gas agreements with Russia. President Viktor Yanukovych has instructed Prosecutor-General Oleksandr Medvedko to take legal actions against people who are responsible for the deterioration of financial situation of Naftogaz Ukrainy. Dubyna was a senior economic advisor to Volodymyr Zelensky during the 2019 Ukrainian presidential election. The Kryvorizhstal steel company during Dubyna's tenure as the Director General had sponsored Zelensky's local KVN team.
