Jón Kalman was born in Reykjavík. He grew up there and in Keflavík. From 1975 to 1982, he lived in western Iceland, where he worked in different jobs after having finished high school.

From 1986 to 1991, he studied literature at the University of Iceland, but did not pass an important exam. During this time, Stefánsson taught courses at high schools and writing articles for the Icelandic newspaper Morgunblaðið. Between 1992 to 1995, he lived off various jobs in Copenhagen, Denmark. Afterwards he returned to Iceland and worked as a librarian for the Municipal Library in Mosfellsbær. Since then he has been living as an independent author in Iceland.