Was pope Leo IX excommunicated from the Roman Catholic Church?

No, Pope Leo IX was not excommunicated from the Roman Catholic Church; he was the pope from 1049 to 1054. However, he is notable for his role in the East-West Schism. In 1054, he excommunicated Patriarch Michael I Cerularius of Constantinople, which contributed to the formal split between the Roman Catholic and Eastern Orthodox Churches. Leo IX died shortly after the excommunication, and he remained recognized as a legitimate pope.