Not much is known about his family background or early career, since he was a novus homo, meaning not belonging to a traditional family of Roman aristocrats. He managed, nevertheless, to be elected consul for the year of 260 BC, at the outbreak of the First Punic war. As junior partner of the patrician Gnaeus Cornelius Scipio Asina, Duilius was given the command of the rear fleet, not expected to see much action. However, the naivety of Scipio Asina got him captured in the Battle of the Lipari Islands, leaving Duilius as senior commander. He encountered Hannibal Gisco and the rest of the Punic fleet soon afterwards.
The following Battle of Mylae was a stunning victory for Rome, mainly due to the use of the corvus boarding device. Duilius captured several enemy vessels, including Gisco's flagship, and was thus the first Roman successful in a naval engagement. He was awarded a triumphal parade featuring the ramming "beaks" of captured Carthaginian warships that later would adorn a column, the Columna Rostrata C. Duilii, erected in Duilius' honor in the Roman Forum. When in Rome, he also had the honor of being accompanied by a torch-bearer and flute-player whenever he went out at night.
Four Italian warships were named after Duilius:
Lucius Valerius Flaccus
Tiberius Otacilius Crassus
| Consul of the Roman Republic
With: Gnaeus Cornelius Scipio Asina
Lucius Cornelius Scipio
Gaius Aquillius Florus