He was born in Ataun (Guipuzcoa) the 23rd January 1936. He made religious studies from 1947 to 1959 (Humanities, Philosophy and Theology). In 1959 he took the holy orders and then he left priesthood in 1977. He worked for ten years in a foundry and finally he took a teacher place in the ikastola of Zumaia. Nowadays he lives in Zumaia and he is retired.

Dorronsoro has been a great researcher on bertsolaritza. He published the history of bertsolaritza (1789-1980) in two volumes next to the most important classification of the melodies used by the improvisers. He has also identified each one of them. On the other hand, he was one of the main promoters of bertsolaritza in formal education, creating and publishing didactic material based on bertsos, according to him, the best form to work simultaneously on Basque language and music. He created one of the first schools of bertsolaris in the ikastola of Zumaia in 1980, where he worked until 1999.

He is a honorary member of the Association of Friends of Bertsolaritza.