Lee claimed his second directing Oscar on Sunday night in an upset over Steven Spielberg, who had been the heavy favorite for "Lincoln." Lee won the same award in 2005 for "Brokeback Mountain."
"It was a very sweet moment for me," he said backstage.
"Life of Pi," a shipwreck story told in 3-D, won a leading four trophies, including musical score, cinematography and visual effects.
"It's a miracle that I could make this movie," Lee said. "I carried the anxiety for a very long time, four years. It's a philosophical book and expensive movie, a scary combination."
The surprise blockbuster about a youth trapped on a lifeboat with a Bengal tiger made Lee want to work in 3-D again, calling it "a very new cinematic language."
"The bad news is it's too expensive. It's very hard," he said. "Once it gets cheaper and easier, more filmmakers are going to dive into it. I see there's quite a brilliant future in it. I will try again if I can afford it."
The Taiwan-born Lee who grew up watching American movies thanked his home country, where he said 90 percent of the film was shot.
"They gave us a lot of physical help and financial help," he said. "I'm glad that Taiwan contribute this much to the film. I feel like this movie belongs to the world."
Lee recalled how he only spoke broken English when he made "Sense and Sensibility" in 1995, his first mainstream Hollywood film.
"You can overcome cultural barriers, but you have to be diligent," he said.
Lee was reminded backstage that Sunday was the last night of the Chinese new year, a 15-day celebration.
"This is a great night for me and everybody who liked the movie, particularly in Asia," he said. "I wish them a happy new year of the snake, everybody gets lucky."
Lee became the 19th director to win multiple directing Oscars. He was nominated in 2000 for "Crouching Tiger, Hidden Dragon."
Besides Spielberg, Lee beat out nominees Michael Haneke ("Amour"), David O. Russell ("Silver Linings Playbook") and Benh Zeitlin ("Beasts of the Southern Wild").