Even though Regensburg in Bavaria is often quoted in literature as Isserlein's birthplace it is now clear that he was born in the Styrian Maribor or Marburg an Drau, present-day Slovenia, in the last decade of the 14th century. As a son of R. Petachia of Maribor he came from a well-known scholarly family. His grandfather Rabbi Chaim, named Henschel of Hainburg or Hetschlein of Herzogenburg was well-versed in Jewish learning, which held especially for Isserlein's great-grandfather R. Israel of Krems. R. Shalom of Neustadt was related to him.