son of Eberhard, Frankish margrave of Friuli, king of Italy from 888 (as Berengar I), and Holy Roman emperor from 915. He was the founder of a line of princes of the 9th–11th century who in popular Italian histories are ranked incorrectly as national kings. Through his mother Gisela he was a grandson of the Carolingian emperor Louis I the Pious.

After the fall of the emperor Charles III the Fat, Berengar, margrave since c. 874, was elected king of Italy in 888 at Pavia. He acknowledged the overlordship of the East Frankish king Arnulf, and from early 889 he was confined to northeastern Italy by Guy of Spoleto (d. 894), who at that time ruled the rest of Italy. After the death of Guy's son and successor, Lambert (898), Berengar finally was recognized throughout the kingdom.

In 899 Berengar was defeated on the Brenta River by the invading Magyars. In 900 King Louis of Provence (the future emperor Louis III the Blind) was invited to Italy by a group of nobles antagonistic to Berengar. Louis was crowned king of the Lombards and then, in 901, was made emperor by Pope Benedict IV. Within a year Berengar had expelled Louis from Italy. Louis returned, however, and was captured at Verona on July 21, 905, blinded, and sent back to Provence. Berengar himself was crowned emperor by Pope John X in 915. But once again he was challenged by some Italian noblemen, who in 922 called in King Rudolf II of Burgundy. Rudolf defeated Berengar the next year at Fiorenzuola, near Piacenza. The following spring Berengar was murdered by one of his own men, and there were no further western emperors until Otto I, who was crowned emperor in 962.