By his early 20s, Clementi had not only become a celebrated pianist, conductor and composer, he was also a prosperous businessman. One of the few musicians of his time who had a hand for making money, Clementi earned a small fortune by selling pianos and printing musical scores.

He composed over 60 sonatas for piano. Austrian pianist Gottlieb Wallisch performed Opus 40 in the Beethovenhaus as part of the 2007 Beethovenfest.