[2] Quinctius was elected consular tribune in 438 BC together with Mamercus Aemilius Mamercinus and Lucius Julius Iullus.
They continued hostilities against the Fidenates and their leader Lars Tolumnius, which would result in the death of four Roman legates sent as ambassadors.
The four legates, Gaius Fulcinius, Cloelius Tullus, Spurius Antius and Lucius Roscius, would later be honoured with statues on the Rostra.
Scholars generally favour Lucius Quinctius as the consular tribune of 420 BC and that the Fasti has confused the two brothers.
The college, including Quinctius, consisted of two of his former colleagues from 425, Furius and Sempronius, and a consular newcomer, Marcus Manlius Vulso.