Born in Salzburg (Austria), he spent much of his youth travelling around Europe with his sister and father, who exibited the children as musical prodigies. He began to give performances with his sister at the age of six. He spent some years unhappily in the service of the Archbishop of Salzburg, but after 1781 he earned a precarious living as a freelance performer and composer.

He wrote his first symphonies at the age of eight, and thereafter produced a continuous series of major and minor works until his death. Only a few of his masterpieces were hailed with enthusiasm during his lifetime, and he was constantly disappointed in his applications for steady employment. Many of his contemporaries found his music difficult and obscure, only a few fellow-composers (including Haydn) recognised the extent of his genius.