Kornaros was born in or near Sitia, Lasithi prefecture on March 26, 1553 to a noble family of Venetian ancestry. He moved at age 35 to Heraklion where he married Marietta Zeno. The couple had two daughters.
Kornaros is best known as the writer of the lengthy poem Erotokritos, dealing with themes such as love, honour and courage. The poem is written in characteristic Cretan dialect and rhyme (15-syllables also used in the traditional form of short poetry mantinades). "Erotokritos" first became popular in Italy but became enormously popular back in Crete where its words were sung to music.