Born in 1950 in Yerevan, to a teacher's family, started painting in early childhood. His works were demonstrated at many exhibitions and got complimentary coverage in the media when he was still a student of the secondary school.

Being a student of the Painting and Drawing faculty of the Armenian Pedagogical Institute, in 1975 Garnik Hovhannisian won the 1st prize of the republican painter's contest dedicated to 100th anniversary of the great Armenian poet Avetik Isahakian.

He graduated from the Institute in 1977, and since then, his paintings and graphic artworks were demonstrated at a number of exhibitions in Armenia and abroad, including All-Union events of the former Soviet Union.

He taught painting in art schools, at the Pedagogical Institute and different art studios.

He is a member of the Painters Union of Armenia.

A personal exhibition Garnik's works named "Ode to Armenia" passed with great success at the Painter's House of Armenia on 18-25 November 2003.

In March-April, 2004, an exhibition of his works was presented in the building of the Central Bank of Armenia.

Another personal exhibition was held in the same year at the U.S. Embassy in Yerevan.

In the fall of 2005, personal exhibitions were held in Los Angeles and Fresno, California.