At 14, he joined the Academia Nacional de Bellas Artes, studying drawing and engraving with Sergio Sergi, sculpture with Lorenzo Dominguez, and painting with Francisco Bernareggi and Ramón Gomez Cornet.

In 1957, he won the competition held by Emecé Editores to illustrate the part 2 of the Miguel de Cervantes novel Don Quixote,[5] and the José Hernández poem Martín Fierro in 1959.

In 1971, his works were exhibited in European galleries such as Villa Giulia in Rome, the Eidos of Milan, and the Bedford in London.

[1] In 2005, to mark the 400th anniversary of Don Quixote part 1 being published, the Museum of Design and Illustration held a tribute exhibition at Buenos Aires' Museo de Artes Plásticas Eduardo Sívori where Alonso's prints and original drawings were displayed.

[7] Following the coup of 1976, and the disappearance of his daughter Paloma (born 25 July 1956) the following year, Alonso went into exile in Italy, and in 1979, he moved to Madrid.