The Academy of Motion Picture Arts and Sciences also gave Oscars to Meryl Streep playing former British Prime Minister Margaret Thatcher in "The Iron Lady," marking Streep's third Academy Award in 17 nominations, and veteran Christopher Plummer made history by becoming the oldest winner ever at age 82 with his role as an elderly gay man in "Beginners."
But it was the "The Artist," a French movie that has been called a love letter to old Hollywood by its makers, that charmed Oscar voters. Made in the style of old silents, it tells a romantic story of a fading star in the era when silent movies were overtaken by talkies.
"The Artist" collected Oscars for its star Jean Dujardin and director Michel Hazanavicius, as well as for musical score and costume design.
"I am the happiest director in the world right now. Thank you for that," Hazanavicius told the audience of stars including George Clooney, Michelle Williams, Angelina Jolie, Brad Pitt and members of the Academy.
Dujardin was equally excited, exclaiming "I love this country" before thanking the Academy, the film's makers and his wife, and calling silent actor Douglas Fairbanks an inspiration.
Streep's victory surprised Oscar pundits who thought Viola Davis would win the Academy Award with her portrayal of a black maid in a southern white home in civil rights drama "The Help."
But Streep's turn as an elderly Thatcher who is slipping into dementia was too good to be ignored. It was Streep's third Academy Award out of 17 nominations, and even she reckoned that Oscar voters would think she's been there, done that. Backstage she termed it "Streep fatigue" to reporters.
"When they called my name, I could feel America saying, 'Oh why her again?' But whatever," she joked. Yet even the steely veteran could not hold back the emotion of an Oscar victory. When she thanked her huband and talked about her career she came close to breaking into tears, and backstage she said it made her feel like a kid again.
Making Hollywood history
Veteran Plummer, a star of classic film "The Sound of Music," won his first ever Oscar for his portrayal of an elderly gay man who comes out to his family in "Beginners."
"You're only two years older than me, darling. Where have you been all of my life," he said, looking at his golden Oscar, which was celebrating its 84th awards ceremony.
Spencer, a relative newcomer in contrast to Plummer, had to hold back tears as she accepted her trophy for her portrayal of a black, southern maid in civil rights drama "The Help."
"Thank you Academy for putting me with the hottest guy in the room," she said holding her Oscar in her hand. She then went on to talk about her family in Alabama and could not hold back her tears as she joyously accepted her trophy.
Director Martin Scorsese's "Hugo," which like "The Artist" pays tribute to early filmmaking, came into the night with a leading 11 nominations - one more than "Artist" - and also picked up five wins. But its Oscars came in technical categories cinematography, art direction, sound editing and mixing and visual effects.
Another highly touted movie, family drama "The Descendants," walked off with only one Oscar, adapted screenplay for its writer and director Alexander Payne and co-writers Nat Faxon and Jim Rash. Woody Allen won for original screenplay with "Midnight in Paris," but he was not on hand to accept his trophy.
In other major wins, the foreign language film award went to Iranian divorce drama "A Separation." "I proudly offer this award to the people of my country, the people who respect all cultures and civilizations and despise hostility and resentment," said its director, Ashgar Farhadi.
Asked backstage how he thought the Iranian government might respond, he said he really did not know. "I can't predict what's going to happen," he said.
"Rango" claimed best animated film, while "The Iron Lady," won a second award for makeup.
The documentary category saw another major surprise for "Undefeated," a film about football players in a poor struggling community to make their lives better. "Paradise Lost 3: Purgatory" had been widely picked to win by pundits.
One of the film's makers, T.J. Martin, used an expletive onstage in a sign of his joy, but it was edited out for television audiences. He apologized backstage in the press room.
Comedian Billy Crystal, who returned to emcee the show for the ninth time, had the crowd laughing loudly with an opening video in which he was edited into the year's top movies.
He was kissed by George Clooney on the lips in a scene out of "The Descendants" and even ate a tainted pie from "The Help." He opened with a monologue in which he joked: "there's nothing like watching a bunch of millionaires present each other with golden statues" and sang a comic song about the movies.
Other highlights included stars like Morgan Freeman, Tom Hanks, Adam Sandler and others in brief video vignettes telling audiences why they loved movies. The clips highlighted this year's themes of reminding people what makes movies magical.
Finally, Hollywood's biggest fashion parade on the Oscar red carpet heated up with Michelle Williams in a stunning red dress from Louis Vuitton, "The Help" star Jessica Chastain in a dazzling Alexander McQueen black and gold embroidered gown, while Gwyneth Paltrow chose Tom Ford and white, a popular color.