Saint John gained the name of Chrysostom (Greek for golden mouth) for his zeal and clarity of his sermons which appealed especially to the common people.

His time as archbishop of Constantinople were difficult because he often preached on the misuse of money. This annoyed Eudoxia, the wife of the emperor Arcadius, and his rival archbishop Theophilus. He was banished from the city and he died in exile.
Sorces use wikipedia and Britannica.