Daniel Nguyen is a graduate of Santa Barbara High School and the University of Southern California (USC).

In the 2009 US Open, he and former teammate JT Sundling were defeated 3–6, 6–2, 6–1 in the first-round of the men's doubles tournament by Máximo González and Juan Mónaco.

They qualified after winning the Boy's Junior National Tennis Championship Doubles Title in 2009.

[2][3][4] He won the silver medal in an all-Vietnamese men's singles final at the 30th SEA games in the Philippines in December 2019.

His compatriot Ly Hoang Nam in the final won the first ever tennis gold medal for Vietnam.