A few, scattered Roman coins were found in the municipality, but the earliest known settlement dates back to the Middle Ages. During the Middle Ages Hasliberg was part of the Vogtei of Oberhasli and the parish of Meiringen. In 1334 the entire Oberhasli Vogtei was acquired by Bern. For most of their history, the residents of Hasliberg raised crops in the valleys, raised cattle and horses in seasonal alpine herding camp and produced cheeses from the milk. Beginning in the 14th century they began to mine iron ore from the surrounding hills and mountains. Blast furnaces were built in the Mühletal, and many residents cut timber or produced charcoal for the furnaces. They also made a small amount of money from traffic over the Brünig Pass. Beginning in the High Middle Ages, the Hasliberg often fought with the neighboring municipalities of Lungern and Kerns over grazing land in the high alpine meadows.
