Hamilcar, upon taking command in the summer of 247 BCE, punished the rebellious mercenaries (who had revolted because of overdue payments) by murdering some of them at night and drowning the rest at sea, and dismissing many to different part of northern Africa. With a reduced army and fleet, Hamilcar commenced his operations. Romans had divided their forces, Consul L. Caelius Metellus was near Lilybaeum, while Numerius Fabius Buteo was besieging Drepanum at that time. Hamilcar probably fought an inconclusive battle at Drepanum, but there is cause to doubt this.

Hamilcar next raided Locri in Bruttium and the area around Brindisi in 247 BCE, and on his return he seized a strong position on Mount Ercte (Monte Pellegrino, just north of Palermo or Mt. Castellacio, 7 miles north-west of Palermo), and not only maintained himself against all attacks, but carried on with his seaborne raids ranging from Catana in Sicily to far as Cumae in central Italy. He also set about improving the spirit of the army, and succeeded in creating a highly disciplined and versatile force. While Hamilcar won no large-scale battle or recaptured any cities lost to the Romans, he waged a relentless campaign against the enemy, and caused a constant drain on Roman resources. However, if Hamilcar had hoped to recapture Panormus, he failed in his strategy. Roman forces led by the consuls Marcus Otacilius Crassus and Marcaus Fabius Licinus achieved little against Hamilcar in 246 BCE, and the consuls of 245 BCE, Marcus Fabius Bueto and Atilius Bulbus, fared no better.