He set a personal best record with a time of 7 minutes and 50.2 seconds. He was 3.65 seconds faster than silver medalist Yosida Keisuk of Japan.
Before his gold medal effort Friday morning, Hoang came fourth in the 400 meters freestyle event.
This is the second gold medal for Vietnam at 2018 Summer Youth Olympics. The first one was won by weightlifter Ngo Dinh Son in the 56 kilogram men’s category, lifting a total of 262 kilograms. Nguyen Thu Trang won silver in the 44 kilogram women’s category.
Hoang had previously won two medals for Vietnam at the Asian Games 2018 in August – a bronze in the 800 meters freestyle race with a time of 7 minutes and 54.32 seconds; and a silver in the 1,500 meters freestyle competition.
The 2018 Summer Youth Olympics is being held in Buenos Aires, Argentina, gathering 3,997 athletes from 206 countries and territories. It will continue until October 18, 2018. It is the first Summer Youth Olympic Games to be held outside of Asia, also first in the southern and western hemispheres, and the first Youth Games for either summer or winter to be held outside Eurasia.
A Vietnamese contingent of 13 athletes are participating in seven sports: track and field, swimming, gymnastics, weightlifting, badminton, taekwondo and rhythmic gymnastics.