He was a Levite, the son of Gershom and Moses' grandson, living in the town of Bethlehem in Judah. Though Levites were to be taken care of by the towns they served, Jonathan sought a better place. This would lead to private duty in an Ephraimite household before he followed what seemed to be a better opportunity in the relocated tribe of Dan.
The name Jonathan (Heb: וִ֠יהתָוֹנָן, Yehonathan) means "Yahweh has given". Such a name at birth would be that of a faithful man, or at least one who observed the authority of Yahweh as giver of blessings. In this case, Gershom the son of Moses, would have been of those grew up in wilderness of the tribes of Israel. Not of the line of Aaron, Gershom would have been a Levite, and thus a supporting minister to the priesthood.
Gershom had been born near the end of his father's time as a shepherd in Midian. He and his brother were quite young as they began the journey toward Egypt with their mother Zipporah and father. As a child of Moses, he would have honored his father as he heard the word of Yahweh from the sanctified tent of meeting. After he turned thirty, he would begin his duties in the tabernacle. Apparently, he would wait until his retirement at fifty to marry and begin a family as an "elder" in the new land.
Jonathan, the son of his old age, would be born sometime in the days of the judges. Given his genealogy, Jonathan would have been born not much later than than the death of Joshua (in about 1350 BC). Young Jonathan may have known, or heard, of the great general Joshua. However, the leader of the tribes as he grew up was most likely Othniel, Caleb's nephew, a mighty solder in Joshua's army. The influence of the priesthood at Shiloh, though, did no reach far in those days. While the judges made their circuits, most people lived by their own rules.
Adult Ministry and Apostasy
Levites were called to serve in the towns of the tribes, with no land of their own except for farms outside town. And so it was that Jonathan served among those in Bethlehem. But a time would come when he would travel to find a place of his own. On the way from Bethlehem to Shiloh, he came upon Micah, a leader in the Tribe of Ephraim. The older man asked of him an unlawful arrangement: to become a private priest with a salary of ten pieces of silver per year as well as room and board.
For a time this worked well, for Jonathan served as spiritual adviser to a dysfunctional family. However, this would not last. Sometime later, for the leadership of the tribe of Dan sent out five spies to find a place to settle down. Though they had been allotted much land in the lowlands of Canaan, they had been unable to secure it. An army of 600 men readied themselves to take whatever easy pickings was found. On their way to the target--an undefended and peaceful town outside the bounds of the allotments--the spies found Micah's house.
Jonathan acted the part of a priest, praying on their behalf to the idols using a ceremonial garment called an ephod. He gave them a "blessing" for their journey. The spies brought the army with them when they returned to the household of Micah. By force, they took everything of "spiritual" value, including Jonathan, and successfully destroyed Laish, in the far north, renaming the burned out city Dan. Jonathan became the high priest of a new religion in Dan. He would have children, which he would ordain as priests.