Much like his father, John II is little mentioned by chroniclers despite two decades on Gothenland's throne.
It was during John's reign that Gothenland attempted to legitimise its activities in Prussia, Lithuania and Livonia. A petition to the papacy to start a new crusading order exclusively against the pagan Balts (the Teutonic Order split its activities between the Baltic and the Holy Land) was submitted in 1296. The Teutonic Order of course would not counter a rival crusading order on their patch of course. It did force the Germans to come to terms with the Gothenlanders in their midst however. So while this never really took off as an idea a certain co-operation with the Teutonic Order did appear. The Gothenlanders allowed the Knights access to Memel whilst their capture of Ruse-moter in Sambia was approved by the Grandmaster himself.
The only direct history of John's reign mentions a bloody feud with his cousin Karl, Duke of Halland. Karl had married Princess Kristin of Hordaland and it seems nobles began to stir up suggestions that Karl, with a royal marriage, would make a better king than John, who was married to a relatively low noble, Elizabeth of Landeryd. It is unknown what John did exactly to stir up their passions in the first place. However he certainly quashed any hint of usurpation; Karl and his closest retinue to a feast at a hall near Vadstena, ostensibly to smooth over relations, but there John's knights drew swords and slew Karl and his retinue. Kristin and her two sons Olaf and Inge were unharmed however, perhaps to avoid an unnecessary war, and taken into John's court.
John would die in 1304. Each of John and Elizabeth of Landeryd's three children, Karl IV, Eric II and Sophia would rule Gothenland in succession.