Lawrence stumbled as she took the steps to the Oscar stage, falling to her knees in her flowing Dior gown. That drew a sympathetic ovation from the auditorium.
She remained endearingly flustered during her acceptance speech, thanking her family, those who worked with her on the film and wishing a "Happy Birthday" to a fellow nominee, Emmanuelle Riva of "Amour," who turned 86.
"Look at this dress. I tried to walk up stairs in this dress," Lawrence said of her white, floor-length gown. "I think I stepped on the fabric and they wax the stairs."
Lawrence said she thought of a "bad word" to say when she tumbled but kept it to herself.
She had already been bleeped by ABC when she let loose with a four-letter word while joking with Kristin Chenoweth on the red carpet.
Asked how she got ready for the day, Lawrence said it was "chaotic" from the start, with her family taking over the house to prepare for the big evening.
After fumbling for a more descriptive answer, she apologized: "I'm sorry. I did a shot."
It was the first Oscar for the 22-year-old Lawrence, who was also nominated for "Winter's Bone" in 2011.
Daniel Day-Lewis won the Academy Award for best actor for his exactingly authentic performance as President Abraham Lincoln in Steven Spielberg's historical drama.
He's the first to ever win the best actor Oscar three times. He's been nominated five times, winning for "My Left Foot" in 1990 and "There Will Be Blood" in 2008.
Day-Lewis spent a year preparing for "Lincoln," and, in his customary method, remained in character during the production. His widely-expected Oscar win further cements his status as the most admired actor currently working.