Danny “The Lion” Leo won’t be leaving his cage any time soon.

The former acting boss of the Genovese crime family pleaded guilty yesterday to racketeering charges, along with a nephew who the feds say served as his “primary lieutenant.”

Danny Leo, 69, and Joseph Leo, 48, both admitted to loan-sharking and conspiring to run an illegal gambling business, according to Manhattan US Attorney Preetinder Bharara.

The guilty pleas mean that Danny Leo could spend another 51 months in the slammer after he finishes a 5-year stretch next year for extortion.