- "And his PA is coming, Father Jessup, the most sarcastic priest in Ireland."
- ―Father Ted Crilly
- Mrs. Doyle: "OK ... would you like a cup of tea?"
- Jessup: "No, I'd rather die of thirst."
- — An example of Father Jessup's sarcasm
Father Jessup is a priest and the personal assistant of Bishop Brennan. He is famous for his sarcasm, nearly always saying the opposite of what he means when directly spoken to. He was portrayed by Irish actor Ian Fitzgibbon.
He accompanied Bishop Brennan to Craggy Island Parochial House to investigate a claim that an image of Bishop Brennan had been appearing on the skirting board of the house. This was really just an excuse to get Bishop Brennan to come to the house, in order for Ted Crilly to kick him up the arse. While he was there, Jessup confused Mrs. Doyle, by his frequent use of sarcasm. Mrs. Doyle, however, learned to ignore Jessup's sarcastic comments by doing the opposite of what he said.
Jessup was then captured by Father Jack Hackett and locked in his underpants hamper. After many hours trapped inside the hamper, he caught the attention of Mrs. Doyle, and cried for help. However, as Mrs. Doyle had learned to do the opposite of what Jessup said, she left him in the hamper. He is later seen using a lighter to increase visibility inside the hamper, and is sporting a long beard, suggesting that he was in there for many days. Although it is unknown what happened to him after this point, it is presumed he was later released.
- 'Jessup' is a variant of 'Joseph', and means 'Jehovah increases'.
- Jessup's first name is never revealed.