Archaeological excavations in Mi'ilya gives indication of inhabitation from the Late Bronze Age and Iron Age, as well as Hellenistic, Roman, Byzantine, Crusader, Mamluk and Ottoman periods.
The King's castle in Mi'ilya dates back at least to 1160, when King Baldwin III of Jerusalem granted title to it to a certain John of Haifa and his heirs. In 1182, Baldwin IV granted it to his uncle, Jocelyn III. At this time it was called "The new castle in the mountains of Acre". By 1187, the castle fell to Saladin. Later, in the early 1200, ownership passed to the Teutonic Knights. However, the importance of the castle of Mi'ilya was by this time superseded by the Montfort Castle.