The conductor George Szell made them into one of the world's best orchestras. When he started conducting them after World War II he told twelve of the players that they had to leave. Another twelve musicians were so angry that they left as well. Szell then improved the orchestra during the 24 years he was with them. Even now the orchestra is so good because of what Szell did for them.
Today's conductor of the Cleveland Orchestra, Franz Welser-Möst, continues to conduct the orchestra in Cleveland as well as touring with them all over the world. They perform regularly in the summer at the Blossom Festival in Cuyahoga Falls, Ohio, and also in Miami, Florida, and in the Musikverein, Vienna.