Gagik Kostandyan was born on April 15, 1954 in Yerevan.

Mr. Kostandyan graduated with a degree in economics from Yerevan State University in 1977. He also received a law degree from Yerevan State University in 1995. He is a Legal Sciences PhD, and academician of the International Academy of Environment and Society. He was awarded government medals in 1980 and 1988.

From 1969-1972 he was a worker in Bardzraberdzshin Administrative Office in Yerevan. From 1977-1978 he was an economist in the Masis Universal Store. From 1977-1978 he worked in the Ministry of Internal Affairs and from 1996-1999 he was the executive director of Gor Ltd.

1999-2003 was his first term as a deputy of the NA (electoral district # 3) and he was on the NA Standing Committee on Defense, National Security and Internal Affairs. He was not a member of any of the faction or deputy group. On May 25, 2003 he was reelected to the NA from the proportional list of the National Unity Party and is currently on the NA Standing Committee on Defense, National Security and Internal Affairs. He is a member of the National Unity Faction. He has no political party affiliation.

Mr. Kostandyan is married and has three children.