Kostyantin Zhevago was born on January 7, 1974 in Iul'tin village (Magadan Oblast, Russia) in the family of a mining Engineer.
In 1991 Kostyantin Zhevago entered the Kyiv National Economic University, taking «Accounting and analysis of external economic activity» specialization. In 1996, he graduated with a master's degree in economics.
While studying Kostyantin Zhevago began a career in the position of "Finances and Credit" chief financial officer (Ukrainian: ЗАТ "Фінанси та Кредит", Russian: ЗАО "Финансы и Кредит"), holding this post from 1993 to 1996. From 1996 to 1998 he holds posts of "Finances and Credit" President, public corporation "Poltava ore-dressing and processing enterprise" (Ukrainian: ВАТ «Полтавський ГЗК», Russian: ОАО «Полтавский ГОК») council deputy and is member of public corporation "Ukrnafta" (Ukrainian: Dfn «Укрна́фта», Russian: ОАО «Укрна́фта») supervisory board.
In Ukraine Kostyantin Zhevago conducts active political activity. In the period of March 1998 — April 2002 he holds the post of a State Deputy of Ukraine of 3rd convocation from 149th electoral district (Poltava Oblast). June 1998 — Zhevago Kostyantin is a member of parliament committee of questions of economic policy, state economy management, property and Investments.
"Finances and Credit" bank was founded in 1990 and by the size of assets it was considered one of the largest banks of Ukraine according to classification of National Bank of Ukraine. By April 1, 2009 authorized capital stock of the bank made 2 billion UAH, net wealth made 18,316 billion UAH, bank liabilities — 15,840 billion UAH. The loan portfolio made 15,880 billion UAH, loan portfolio of natural person — bank clients — 5, 983 billion UAH. By April 1, 2009 the bank system included 16 branches and 326 departments in all areas of Ukraine. The basic shareholders of "Finances and Credit" bank on 01.04.2009 were the close corporation "F&C Realty" (46,67%), LTD "Askaniya" (48,88%) and National joint-stock company "Naftohaz Ukrainy" (0,63%). According to the Ukrainian Bank Association data, by April 1, 2009 the bank occupied the 13th place among 162 operating in the country. On 17 December 2016 the National Bank of Ukraine withdrew the banking license of Finance and Credit and liquidated the bank.
April 2002 to April 2006 — post of a State Deputy of Ukraine of 4th convocation from 150 electoral district (Poltava Oblast). June, 2002 — member of parliament committee of questions of legal policy, member of Verkhovna Rada permanent delegation in PACE.
In 2003 Kostyantin Zhevago defended a candidate's dissertation «International Investments and effective economic development» in the Kyiv National Economic University.
May 2006 to April 2007 — State Deputy of Ukraine of 5th convocation from Yulia Tymoshenko Bloc.
Since December 23, 2007 Kostyantin Zhevago holds a post of State Deputy of Ukraine of 6th convocation in the list of Yulia Tymoshenko Bloc. Leader of deputy group of inter-parliamentary connections with Japan. He missed all 51 parliament sessions in 2010.
According to Forbes, he is Ukraine's youngest Billionaire. In March 2012 Forbes placed him on the Forbes list of billionaires at the 719th place with $1.8 billion.
In the 2014 parliamentary election Zhevago was re-elected into parliament again as an independent candidate in single-member districts number 150; this time with 43.81% of the votes. He again did not join a faction.