Carmelo Sobrino was born in Manatí, Puerto Rico, in 1948. He is the son of Trinidad Arroyo and Carmelo Martínez. When his father died, Sobrino moved to the country with his grandparents, and came into contact, for the first time, with the art of his grandmother, who was a maker of musical instruments and a wood carver.

Inspired by the signs that he saw around him, he started to draw letters, and for a while, made signs and practiced calligraphy. The artist studied construction drawing at the Miguel Such Vocational School, in Arecibo. His first formal art teacher was the painter Oscar Colón Delgado. Later, in the sixties, he attended the School of Plastic Arts, Institute of Puerto Rican Culture, where he studied painting, sculpture, glass and graphics with great masters: Frank Cervoni, Carlos Raquel Rivera, Rafael Tufiño and Augusto Marín among others.

Sobrino traveled to Mexico, the United States, the Dominican Republic, Jamaica and Europe, where he got acquainted with and was influenced by the great painters of the world. In 1969, he co-founded with Antonio Martorell the "Alacrán Workshop" to nurture the talent of drop-out kids by teaching them graphic arts.

In Spain, in 1981, Sobrino directed a project of traveling exhibitions of murals by Spanish and Puerto Rican artists. He has taught at the San Juan Art Students League, Casa Candina, and Turabo University in Caguas.

Sobrino's work has been shown in important solo and collective shows in Puerto Rico and internationally, most recently the International Painting Biennial of Florence, in the year 2000. Lately he has received several commissions to create public works, among them the mural Horizon , at the Puerto Rico Art Museum (1999) and the ceiling mural at the lobby of Taboas Theater, in Manatí, Messenger Constellation.