What Mr. Park does do in his video is parody the area’s reputation for pretentious displays of wealth. In one scene, a man in a yellow suit and oversized sunglasses saunters over to a red sports car; in another, the rapper himself prances in a tuxedo between glamorous women.

Some of that flaunting of wealth is apparent in the actual Gangnam district, which sits across the broad Han River from central Seoul, the South Korean capital. (Gangnam means “south of the river.”) Corporations seem to compete for the most futuristic skyscraper, while residents drive flashy cars, party at wine bars and get their chins tucked at one of the hundreds of plastic surgery clinics.

Gangnam also appears intent on recreating the sort of upper-middle-class American lifestyle seen in Hollywood movies or experienced by returning immigrants or students. The area boasts broad, Los Angeles-style boulevards (with Los Angeles-style traffic jams). Trendy restaurants offer all-day brunch and burritos. (Both are rare in most of Asia.) Seattle-style coffee shops are found not only on every block, but in every building.

To hear many Koreans tell it, Gangnam’s pretensions are just an extreme form of the desires shared by most of this nation of scrappy overachievers. The district’s high-rises emerged from the rice paddies as the South Korean economy took off in the 1960s and ’70s, turning Gangnam into a symbol of the aspirations, and the excesses, of an Asian miracle that also created growing social inequalities.

“It can be too flashy, but we all envy Gangnam because it is the most developed and richest place,” said Yu Jae-yung, 16, a high school student from Chuncheon, a city two hours from Seoul, who visited the Psy stage with friends on a recent frigid morning.

Mr. Park, who is a Gangnam native, did not respond to requests for an interview. But other residents said “Gangnam Style” had accurately captured the split personality of an area that embraces an American-style free-spirited individualism while also trying to keep a Korean identity.

Mr. Park’s song lampooned this predicament with lyrics about his preference for women who act the traditional role of demure female in the daytime, but know how to have fun at night. Residents said that while the reality is not nearly so decadent, they said they were still trying to figure out how to balance Western freedoms and traditional values.