He went to sea at an early age and wound up in New Zealand when he was 29, where he stayed for the rest of his life. He settled first on Stewart Island, working as a whaler, but moved to the remote Fjordland district of the South Island in 1925, where he stayed until shortly before his death. At first he worked on the roads, then turned to gold panning. For 10 years he worked until he saved enough money to return to Sweden for a visit, but just before leaving, it was stolen, and he started all over again.
He was almost self-sufficient, and was famous for his garden and ingenuity, as well as his hospitality. He was one of the very few people to claim to have seen living moa - a genus of birds believed to have become extinct several centuries ago. In 1952 he became ill and was taken to Riverton, where he died in the hospital. Local people never managed to get his name right, and Jules Berg is only the most common of the versions he was known by.