She was the second daughter of Aemilia Lepida and Marcus Junius Silanus Torquatus, one of the Junii Silani.
Her maternal grandparents were Julia the Younger, granddaughter of the emperor Augustus, and Lucius Aemilius Paullus, consul in AD 1.
Lepida married Gaius Cassius Longinus (c. 13 BC - AD 69), a person with remarkable ancestral wealth.
In AD 66, Lepida's husband and nephew were expelled from Rome by Emperor Nero for being a part in Gaius Calpurnius Piso's conspiracy.
Lepida was accused by Nero of black magic and incest with her nephew; her subsequent fate is unknown.