Jöns studied at the University of Cologne and then worked as a canon in Aarhus before he became chancellor to the Scandinavian King Eric of Pomerania. On the death of the archbishop Birger Gregersson (1383-03-11), the King appointed Jöns to take his place, despite protests from the cathedral chapter. Jöns was of Danish descent and had no connection to Uppsala. It is questionable if Jöns ever wanted to work for the church, or if he took the job for his own honour.
Jöns cared mainly for his own pleasure, and left his duties to the chapter. He held parties with female company, and lived a life of luxury and abundance. When his money ran out, he took bribes and borrowed money, eventually putting him in debt, which in return forced him to embezzle Church property.
He also physically abused subordinates churchmen, such as monks and took a young, engaged woman from Stockholm as a mistress. She bore him two children. Finally, the chapter complained to Pope Martin V and, after an investigation, the Pope in 1421 dismissed Jöns from his office.
In 1426 Jöns entered the duties of bishop of Skálholt, Iceland. He was formally ordained in 1430. However, three years after being ordained, the Icelandic people had enough of him, and put him in a sack and drowned him.