Ly, who immigrated from Vietnam in 2008, has been accepted at the University of Pennsylvania for the fall.
At Southern, as the school is called, Ly is known as a humble, intellectual student who scored a perfect 800 on the math portion of his SATs.
"We're proud of him," principal Otis Hackney said. "He's just been an invaluable resource for me as the principal here, in understanding some of the complexities of the issues around South Philadelphia High School."
School officials plan to make an announcement about Ly's award, Hackney added.
The Princeton Prize is awarded annually to one or occasionally two high school students from each of 23 regions around the country. It was established by the university in 2003 "to promote harmony, respect, and understanding" by recognizing students who have a significant, positive effect on race relations.
On Dec. 3, 2009, Southern was rocked by a daylong series of assaults on Asian students carried out by groups of mostly African American classmates. Seven Asian youths went to hospitals and about 50 staged a weeklong boycott.
Last year, the Princeton Prize was awarded to Wei Chen, a boycott leader who demanded accountability from school officials. Ly, then a junior, worked closely with Chen to bring attention to violence issues.
"They're bookends for a phenomenal amount of work around making that school a better place," said Helen Gym, of the advocacy group Asian Americans United, and who works with both youths.
Ly's parents, ethnic Chinese living in Vietnam, fled that Southeast Asian land in 1990, making their way to Thailand. Ly was born there, in a refugee camp, two years later. He was 4 when the United Nations cut off funding for the camps and his family was forced to return to Vietnam.
In the capital of Ho Chi Minh City, formerly Saigon, Ly's parents survived by running a noodle stand. They scraped to pay for their son's schooling, while undertaking a 12-year effort to move to the United States. They arrived here in 2008.
When Ly saw violence at Southern, he felt compelled to act.
"I nominated Duong for the award because of all of his dedication, and all of his work, since the end of the boycott," said Nancy Nguyen, head of the local chapter of Boat People SOS, a Vietnamese advocacy group. "It's a school with really deep wounds, but also this is a city with deep wounds around ethnic conflict . . . I saw him struggling to build an institution to begin to address this issue in a way that's broader than South Philadelphia."
Princeton Prize officials formally cited Ly for helping found the Asian Student Association in September 2010. The group seeks to empower Asian youth citywide and develop solutions to violence against immigrants.
The award, which comes with $1,000, will be presented by Princeton University administrators during an April 27 ceremony at St. Joseph's University.
"Ly's leadership in conciliatory efforts and empowerment training has improved the day-to-day lives of students," said Dora Lee, cochair of the Philadelphia-area prize committee. "We are proud to honor him with this year's Princeton Prize."
Contact staff writer Jeff Gammage at 215-805-5619 or firstname.lastname@example.org.