Fewer than 20 paintings by the Italian artist are believed to still exist.
The 500-year-old oil on panel, titled "Salvator Mundi" ("Savior of the World"), depicts Jesus Christ dressed in flowing robes and holding a crystal orb in his left hand. It's the only painting by Leonardo in a private collection, according to Christie's auction house.
"Leonardo was an unparalleled creative force and a master of the enigmatic. Standing in front of his paintings, it becomes impossible for one's mind to fully unravel or comprehend the mystery radiating from them — both the 'Mona Lisa' and 'Salvator Mundi' are perfect examples of this. No one will ever be able to fully grasp the wonder of Leonardo's paintings, just as no one will ever be able to fully know the origins of the universe," Gouzer added.
Scholars had long believed "Salvator Mundi" was destroyed, until it re-emerged in 2005.
"'Salvator Mundi' is a painting of the most iconic figure in the world by the most important artist of all time," Gouzer said. "Despite being created approximately 500 years ago, the work of Leonardo is just as influential to the art that is being created today as it was in the 15th and 16th centuries."
Christie's had billed the painting as "the greatest artistic rediscovery of the 21st century" and "the last da Vinci," and exhibited it in Hong Kong, San Francisco, London and New York before Wednesday's auction.