He was born in Pesaro into a musical family. He has been playing the triangle with his father since the age of six. In his youth, he learned to play the harpsichord and piano. At the age of ten, he was already singing a solo part for mezzo-soprano in the church and in 1805 he also sang in a theatrical performance, cast in a role for castrates.
From 1807 he learned to play the cello and studied at the conservatory in Bologna. At that time, he changed his first name by omitting the letter "v" to the unique Gioacchino. His first opera was performed in Venice when he was 18 years old. At that time, he had already succeeded with one cantata. His first successful opera was Tancredi in 1813, which included the tragic moment of the protagonist's death.
Two years later, he received a special financing offer from Naples: from 1815 he ran both opera houses there and was obliged to write one opera a year for each of them. In 1816, the Barber of Seville was performed in Rome, and its libretto was created by Pietro Sterbini based on a play written by Beaumarchais. Rossini's version soon overshadowed the one introduced by Giovanni Paisiello more than a quarter of a century earlier. He wrote half of all his operas in this period between 1815 and 1823. In the composition of operas, he was (and is) blamed for a certain superficiality, which resulted mainly from overproduction.
In the 1920s, he lived an intense social life. He accepted invitations to various places in Europe (Vienna, London, and others) and overseas. He personally supported the spread of his music on the streets among the people and to America (Mexico, South America). He inspired a new wave of fashion, both with his music and the Dandy style of dressing and gourmet (to this day, for example, beefsteak with a piece of duck pate is called tournedos á la Rossini).
From 1824 he worked as the music director of the Italian theater in Paris. A year later, at the coronation of King Charles X of France, his first opera composed on a French libretto was performed, under the title The Road to Reims. In 1829, his last opera, William Tell, was also performed. In addition to the 39 mostly comic operas (so-called opera buffa), which he wrote during the two decades before 1829, he composed cantatas, overtures, sacred music, especially masses, instrumental compositions, and other musical formations until his late age.
Although he returned to Italy (he also lived in Florence, for example), from 1855 he lived in France until the end of his life, living in Possy near Paris.
He suffered from many different diseases, including sexually transmitted diseases, but nevertheless lived to a very old age. He died during bowel surgery. He was buried in the Père-Lachaise Cemetery in Paris, from where his remains were transported in 1887 to the Church of Santa Croce in Florence, where his epitaph is also located.