Kononenko was born June 21, 1964, in Türkmenabat|Chardzhou, Turkmen SSR. He is married to Tatiana Mikhailovna Kononenko (née Yurieva). They have a son, Andrey Olegovich Kononenko, and a daughter, Alisa Olegovna Kononenko. Kononenko enjoys reading, and team sports.
Kononenko graduated from the Nikolay Yegorovich Zhukovsky|N. E. Zhukovskiy Kharkov Aviation Institute in 1988 as a mechanical engineer.
Kononenko was awarded the Hero of the Russian Federation medal and the Yu. A. Gagarin Medal of the Cosmonautics Federation, Russia. President of Turkmenistan Gurbanguly Berdimuhamedov awarded the cosmonaut with the order "Star of the President"
After graduation, Kononenko worked at the Russian Space Agency’s Central Specialized Design Bureau TsSKB-Progress in Samara, Russia|Kuybishev, starting as an engineer and working his way up to leading design engineer. His responsibilities included system design, analysis, and development of spacecraft electrical power systems.
 Cosmonaut career
On March 29, 1996, Oleg was selected as a cosmonaut candidate by the Interagency Committee, and from June 1996 to March 1998, he underwent cosmonaut training at the Gagarin Cosmonaut Training Center and on March 20, 1998, was awarded the title of test cosmonaut by the Interagency Qualification Committee. From December, 2001, through April 2002, Kononenko trained as a backup flight engineer for the Soyuz TM-34 vehicle for the third ISS visiting crew. From March 2002, through February 2004, he trained as the flight engineer for the Soyuz TMA vehicle and the Expedition 9 and Expedition 11 primary crews. From March 2004 through March 2006, he trained as part of the group of cosmonauts selected for the ISS Program. In March 2006, Kononenko began training as a flight engineer for the Soyuz TMA-12 vehicle and the Expedition 17 crew.
 Expedition 30
On December 21, 2011, Kononenko, along with André Kuipers and Don Pettit, launched to the International Space Station to join the crew of Expedition 30. He, along with his fellow crewmembers, arrived at the space station on December 23.