Young, 23, who is studying digital filmmaking, was born in the United States, although she has spent more than half her life in the Philippines. Miss France, Marine Lorphelin, and Miss Ghana, Carranzar Naa Okailey Shooter, both medical students, came in second and third, CNN reported.
"No words! Thank you so much for everyone for choosing me. I promise to be the best Miss World ever," Young said.
Her coronation followed more than two weeks of competition held under the threat of violence by Muslim militants. The finals were moved to the resort island of Bali from a location near Jakarta because of security concerns.
The pageant made some concessions to religious conservatives, including replacing the swimsuit competition with one that featured outfits with a local flavor that covered more of the contestants' bodies.
A total of 127 young women from around the world came to Bali for the competition in beach fashion, fitness, world fashion, talent and "Beauty with a Purpose," a category featuring charitable activities.
Young is a college student. Her biography says she has been appearing as an actress and television presenter since she was 15.