She was married to Tassilo prior to 770, to confirm the traditional alliance between Lombardy and Bavaria. The couple had several children.
She resented her former brother-in-law, Charlemagne, for his repudiation of her sister Desiderata and his subsequent destruction of the Kingdom of Lombardy and imprisonment of her parents. She encouraged her husband to rebel against Charlemagne, his cousin. The plan backfired: after word came to Charlemagne that Tassilo had been secretly plotting with the Avars, the enemies of the Franks, Tassilo was put on trial and condemned to death. The sentence was commuted to confiscation of Tassilo's lands and honours; he and his family, including Liutperga, were then tonsured and sent to religious houses.