[2] The Doria family, one of the most powerful dynasties in the history of Genoa, was always related to the political events of the Genoese Republic, however, Oberto's father, Pietro, chose to remain neutral.

[1][3] This appointment, according to the Annali Genovesi, was due to his popularity with the mercantile classes, who had reason to be dissatisfied with the scant successes of the Guelph faction following the fall of the capitano del popolo Guglielmo Boccanegra.

[4] His moves aimed to defend the Genoese Republic's integrity against the Fieschi family, who wanted to create a personal seignory in the Levante Ligure, and the Grimaldi, who had usurped part of the Ponente.

At the same time, he led a prudent conduct against the French Charles of Anjou, then King of Naples and Sicily and also a powerful feudatary in north-western Italy and Provence.

This victory allowed Genoa to regain Corsica and Sardinia, and reduced Pisa to a secondary status in the Mediterranean Sea In 1285 he renounced voluntarily to co-dictatorship, but maintained a role in the Genoese politics.