Hamilton's mother was a German Roman Catholic who travelled to Ireland in 1949 on a pilgrimage, married an Irishman, and settled in the country. His father was a strict nationalist who insisted that his children should speak only German or Irish, but not English, a prohibition the young Hugo resisted inwardly. "The prohibition against English made me see that language as a challenge. Even as a child I spoke to the walls in English and secretly rehearsed dialogue I heard outside," he wrote later. As a consequence of this, he grew up with three languages – English, Irish and German – and a sense of never really belonging to any: "There were no other children like me, no ethnic groups that I could attach myself to".
Hugo Hamilton lives in Dublin. In 1992 he was awarded the Rooney Prize for Irish Literature. Sang impur, the French translation of The Speckled People, won the Prix Femina Etranger in 2004 and Il cane che abbaiava alle onde, the Italian translation of the memoir, won the Premio Giuseppe Berto in 2004. He adapted his memoir 'The Speckled People' for the stage at the Gate Theatre in Dublin in 2011. A new play entitled 'The Mariner', based on the story of his grandfather returning from the First World War, ran at the Gate Theatre in 2014. Hamilton is a member of Aosdána and has been awarded the Bundesverdienstkreuz - order of merit - by Germany for his unique contribution to literature and understanding between Germany and Ireland.