In its ruling, the court in the western Polish city of Wroclaw also forbade the 44-year-old from working with young people for the rest of his life and ordered that he undergo psychological treatment.
The priest was only identified as Pawel K., in line with Polish privacy laws.
He was arrested in December 2012 in a Wroclaw hotel, where he had checked in with a teenage boy, something that aroused the suspicion of hotel workers.
The judge, Maciej Skorniak, said his guilt was not in doubt due to the testimony of a large number of victims.
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The judge described the priest as a "seductive, provocative and dangerous type."
The priest did not admit to any wrongdoing, according to Polish media reports from the court. "I didn't do anything wrong to anybody," he was quoted as saying by TVN24.
The verdict can be appealed.
The archdiocese of Wroclaw said it also plans to prosecute him in a church court and said he would no longer be allowed to exercise priestly functions or wear his clerical garb.