Director Debra Granik's "Winter's Bone," the story of a 17-year-old trying to uncover the fate of her father among the criminal clans of the Ozarks, earned the grand jury prize for American dramas at Sundance, Robert Redford's showcase for independent cinema.
Granik and co-writer Anne Rosellini also won the festival's Waldo Salt screenwriting award for their script, based on the novel by Daniel Woodrell.
The awards came hours after Roadside Attractions bought North American theatrical rights for "Winter's Bone." Roadside plans to release the film this summer.
It was the second-straight Sundance drama winner featuring a breakout role for a young actress. Jennifer Lawrence, whose credits include Charlize Theron's "The Burning Plain," offers a fearless lead performance in "Winter's Bone," which follows Gabourey Sidibe's sizzling debut in the title role of "Precious: Based on the Novel 'Push' By Sapphire," last year's Sundance dramatic winner.
While "Precious" offered a view of a tough urban scene in Harlem, "Winter's Bone" presents a glimpse of a harsh backwoods landscape in Missouri.
"Life is really diverse on this continent that we happen to inhabit," Granik said in an interview after the awards ceremony. "I think there's something to understand that in any county, there's a story that is somewhat universal, but that it's also worthy just to note the differences and appreciate the differences among the counties that make up the 50 states, that make up, then, the larger picture."
The U.S. documentary prize went to "Restrepo," which chronicles the lives of an American platoon fighting in Afghanistan, where the troops have erected an outpost to a fallen comrade, Pvt. Juan Restrepo. The film was directed by journalist Sebastian Junger, author of "The Perfect Storm," and photographer Tim Hetherington.
"We're in the middle of two wars," Junger said. "If our movie can help this country understand how to go forward, we would be incredibly honored by that."
The audience award for favorite U.S. drama chosen by Sundance fans was given to the romance "happythankyoumoreplease," written and directed by and starring Josh Radnor, the star of "How I Met Your Mother."
"Waiting for Superman" - a study of the problems at U.S. public schools that was directed by Davis Guggenheim, who made the Academy Award winner "An Inconvenient Truth" - earned the audience award for U.S. documentaries.
A special jury prize was given to "Sympathy for Delicious," Mark Ruffalo's directing debut, in which he co-stars with friend and screenwriter Christopher Thornton, who plays a paralyzed deejay with the power to heal others but not himself.
Director David Michod's Australian teen drama "Animal Kingdom" earned the dramatic jury prize for world cinema, while the world documentary award went to Danish filmmaker Mads Brugger's "The Red Chapel," chronicling a regime-challenging trip to North Korea.
Javier Fuentes-Leon's Peruvian ghost story "Undertow" won the world-cinema audience honor for dramas, and Lucy Walker's British-Brazilian production "Waste Land," about an art project at a massive landfill, received the documentary audience prize for world cinema.
• U.S. drama directing award: Eric Mendelsohn, "3 Backyards."
• U.S. documentary directing award: Leon Gast, "Smash His Camera."
• World cinema drama directing award and world cinema screenwriting award: Juan Carlos Valdivia, "Southern District."
• World cinema documentary directing award: Christian Frei, "Space Tourists."
• U.S. documentary editing award: Penelope Falk, "Joan Rivers: A Piece of Work."
• World cinema documentary editing award: Joelle Alexis, "A Film Unfinished."
• U.S. drama cinematography award: Zak Mulligan, "Obselidia."
• U.S. documentary cinematography award: Kirsten Johnson and Laura Poitras, "The Oath."
• World cinema drama cinematography award: Mariano Cohn and Gaston Duprat, "The Man Next Door."
• World cinema documentary cinematography award: Kate McCullough and Michael Lavelle, "His & Hers."
By AP Movie Writer David Germain; AP Television News reporter Ryan Pearson contributed to this report