The Topps trading card is a chrome refractors edition sold from 1996-97, Goldin Auctions said on its website. It is just one of two in the world "at its level of perfection."
The auction house called the quality of the card "a condition assessment of unsurpassable magnitude," scoring 10s in every tested category. The bids started at $250,000.
Goldin did not release the name of the card's buyer.
The late Bryant was an 18-time All-Star, known for his remarkable scoring ability and his championship pedigree.
The Los Angeles Lakers legend teamed with fellow All-Star Shaquille O'Neal to win three consecutive NBA titles for the team from 2000 to 2002, and later won two more rings in 2009 and 2010. He retired in 2016.
Last January, Bryant, and his 13-year-old daughter Gianna, were among nine people killed when a helicopter crashed into a hillside in Calabasas, California.
Since the tragedy, memorabilia for the late five-time NBA champion has been showing up on auction sites. Last year, for example, the towel that Bryant draped over his shoulders during his farewell speech in 2016, along with tickets to his final game, sold at a virtual auction for more than $30,000.