The 1942 Best Screenplay Oscar Orson Welles received for Citizen Kane sold for $861,542 on Tuesday (December 20).
Welles wrote and starred in the film, which is highly regarded for its pioneering cinematography.
It was the only Oscar - formally known as an Academy Award - the 1941 film received.
The statue first appeared on the market in 1994 when it was put up for auction by a cinematographer, who claimed Welles had given him the Oscar in lieu of payment.
Welles's daughter Beatrice won the Oscar back in a legal battle and sold it to the not-for-profit Dax Foundation, the statue's consignor.
"This is a testament to the popularity of Orson Welles and his magnum opus Citizen Kane," commented Nate D Saunders, the Los Angeles auction house's owner.
In 1950, the Academy of Motion Picture Arts and Sciences enacted a rule preventing Oscar statues from being sold without the trophies first being offered back to the Academy for $1.
Pre-1950's Oscar's remain fair game, yet their scarcity ensures they are keenly contested by movie memorabilia collectors.
Fewer than 3,000 statues have been presented since the Oscars began in 1929.
In July, a 1942 Best Sound Recording Oscar, awarded to Nathan Levinson for his work on Yankee Doodle Dandy, sold for $89,625.
The world record for an Academy Award stands at the $1.54m Michael Jackson paid in 1999 for David O Selznick's Best Film Oscar for 1939 picture Gone with the Wind.
Laurence Oliver won the 1948 Academy Award for Best Actor for his role in Hamlet. The trophy would be keenly fought over were it ever to appear at auction, such is Olivier's standing in the film and theatre world.
You have a rare opportunity to purchase his autograph today, for £395 (approx. $515).