Mesfin Hagos was born in Azien, Eritrea. He was a founding member of the Eritrean People's Liberation Front (EPLF) in 1977. Before founding that organization he had joined the Eritrean Liberation Front (ELF) in 1966 as an ordinary member. He eventually would become Deputy Commander of ELF Zone 5.Mesfin Hagos left the ELF in 1970 with Isaias Afewerki, Major General Asmerom Gerezgiher,Solomon Weldemariam and Tewelde Eyob. Hagos was a part of the founding leadership of the EPLF.