Born in Bologna, he became canon in his native city, then Cardinal Priest of Santa Croce in Gerusalemme, later treasurer of the Roman Church, papal legate in Germany for Pope Honorius II (1124–30) and later for Pope Innocent II (1130–43). It must be ascribed chiefly to his exertions that Lothair III made two expeditions to Italy for the purpose of protecting Pope Innocent II against the antipope Anacletus II (1130–38). Innocent II appointed him papal chancellor and librarian.
In 1144 he met Roger II of Sicily (1130–54) at Ceprano to clarify the duties of Roger as vassal of the Holy See. Lucius II was not willing to accept the demands of Roger and rejected them, but Roger II forced Lucius II to accept his conditions by sending his general Robert of Selby against him.
The Roman Senate, which practically took all temporal power from the Pope during the pontificate of Innocent II and was dissolved by Lucius II, was resurrected, encouraged by Lucius II's defeat. Lucius II called unsuccessfully for the help of Emperor Conrad III (1138–52) against the Senate and the patrician Giordano Pierleoni, brother of the former Antipope Anacletus II, and finally marched against them with a small army. This fight was lost by Lucius II, too. According to Godfrey of Viterbo, he was seriously injured during this battle (by a thrown stone) and died a few days later from his injuries.