Nguyễn Trần Duy Nhất was born in Nha Trang in the Khánh Hòa Province of Vietnam. He was then raised in Lam Dong in Vietnam's Central Highlands. Duy Nhất has one older sister and two younger brothers. Being descended from the martial arts master who founded the Vietnamese martial art known as Tan Gia quyền, he began practicing martial arts from the age of 3. He then began competing in junior tournaments at the age of 14. Duy Nhất discovered Muay Thai in 2007 when he left to study in Ho Chi Minh City. He first saw the martial art on the film.
Muay Thai career
Nguyễn Trần Duy Nhất made his first Muay Thai appearance at the 2009 Asian Martial Arts Games, competing in the men's featherweight division. He lost 0–5 to Thailand's Kittisak Boonsemsen in the final to win the featherweight silver medal. Duy Nhất then participated in the 2009 Asian Indoor Games, once more in the men's featherweight division. He beat Weerapol Nonting of Thailand, 4–1, in the final to win Vietnam's only gold medal in Muay Thai. He would then make his SEA Games debut at the 2009 Southeast Asian Games held in Vientiane. Competing in the men's featherweight category, he finished in second place to win the silver medal. On July 2, 2013, Nguyễn Trần Duy Nhất would defeat Daniiar Kashkaraev of Kyrgyzstan, 5–0, to win the gold medal in the men's featherweight category in Muay Thai at the 2013 Asian Indoor and Martial Arts Games. On October 24, 2015, Duy Nhất defeated Victor Pinto at THAI FIGHT Vietnam by decision. On September 23, 2017, Nguyễn Trần Duy Nhất fought at the inaugural Asia Fighting Championship event, where he defeated Huang Guang Wan by second-round technical knockout. He appeared at Asia Fighting Championship again, this time fighting Zhao Zhan Shi on September 21, 2018. After three rounds, Duy Nhất was awarded the unanimous decision victory. Nguyễn Trần Duy Nhất made his ONE Championship debut at on September 6, 2019. It was ONE's first event ever held in Vietnam and the first event to feature all-striking matches. He faced Azwan Che Wil of Malaysia, whom he knocked out in the third round. On November 22, 2019, he faced Yuta Watanabe at, where he won with via second-round head kick knockout.
Lethwei career
In 2019, Nguyễn Trần Duy Nhất signed to the World Lethwei Championship to start fighting in lethwei. On February 22, 2019, Duy Nhất made his lethwei debut at, where he defeated Pich Mtes Khmang by knockout at 2:13 of the first round. On August 2, 2019, he returned to World Lethwei Championship at, where he defeated Izat Zaki by unanimous decision.
