Martinez was born in Oeiras, Portugal, in 1963, to Spanish parents. He opted for Spanish nationality in 1978. In Lisbon, he attended (Ar.Co) where he graduated in Fine arts in 1985. During his years at the Ar.Co, Martinez co-authored the "Manifest of the Multi-instrumentalist Painting" which was published in the Portuguese national newspaper, "Jornal de Letras, Artes e Ideias" on 26 June 1984. This manifest was accompanied by an exhibition at the , creating enthusiasm among the new artists and critic.