Zañartu was born on 6 September 1921 in Paris, France, moving to Chile in 1938.

[1] He moved to New York City in 1944 where he was associated with the Atelier 17 print studio.

There he studied under Stanley William Hayter and also taught classes as well as serving as associate director of the studio.

In 1965 he married fellow artist Sheila Hicks with whom he had two children.

[1][3] In 1994 a retrospective of his work was held at the Galería Tomás Andreu in Santiago, Chile.