The black and white film - which tells the tale of an old-Hollywood love story - was named Best Picture, while its star Jean Dujardin took Best Actor and Michel Hazavanicius took home the award for Best Director.
Accepting the Best Actor accolade, first-time nominee Jean, 39 - who saw off stiff competition from Hollywood stalwarts Brad Pitt and George Clooney - gushed: "I love your country. So many of you here tonight have inspired me."
The film also scooped the awards for Best Costume Design and Best Original Score.
Seventeen-times nominated star Meryl Streep was named Best Actress for her portrayal of former British Prime Minister Margaret Thatcher in 'The Iron Lady'.
The 62-year-old third-time Oscar winner kissed husband Don Gummer before taking to the stage at Los Angeles' Kodak Theatre to accept her iconic Oscars statuette.
She joked: "When they called my name I had this feeling I could hear half of America going, 'come on, why her again', but whatever."
Praised by award presenter and her 'Mamma Mia!' co-star Colin Firth for being "unreasonably good", she thanked her colleagues and friends for her "inexplicably wonderful career".
Another big winner of the night was Martin Scorsese's 3D adventure drama 'Hugo' which was victorious in the categories of Best Cinematography, Best Art Direction, Best Sound Editing, Best Sound Mixing and Best Visual Effects.
Christopher Plummer, 82, became the Academy's oldest winner when he was named Best Supporting Actor for his role as a gay father in 'Beginners', while Octavia Spencer picked up the Best Supporting Actress title for 'The Help'. Actor Billy Crystal hosted.
A full list of winners at the 2012 Academy Awards:
Meryl Streep - 'The Iron Lady'
Jean Dujardin - 'The Artist'
Michel Hazavanicius - 'The Artist'
BEST ANIMATED SHORT:
'The Fantastic Flying Books of Mr. Morris Lessmore'
BEST DOCUMENTARY SHORT:
BEST LIVE ACTION SHORT:
BEST ORIGINAL SCREENPLAY:
Woody Allen - 'Midnight in Paris'
BEST ADAPTED SCREENPLAY:
Alexander Payne, Nat Faxon and Jim Rash - 'The Descendants'
'Man or Muppet' - 'The Muppets'
BEST ORIGINAL SCORE:
Ludovic Bource - 'The Artist'
BEST SUPPORTING ACTOR:
Christopher Plummer - 'Beginners'
BEST VISUAL EFFECTS:
BEST ANIMATED FILM:
BEST DOCUMENTARY FEATURE:
BEST SOUND MIXING:
BEST SOUND EDITING:
BEST FILM EDITING:
'The Girl with the Dragon Tattoo'
BEST SUPPORTING ACTRESS:
Octavia Spencer - 'The Help'
BEST FOREIGN LANGUAGE FILM:
'The Iron Lady'
BEST COSTUME DESIGN:
BEST ART DIRECTION:
Robert Richardson - 'Hugo'