Nguyen spent nine seasons in MLS, kicking off with the New England Revolution in 2012. He featured for the Eastern Conference team up until 2018, before joining Los Angeles FC for two seasons, where he lifted the Supporters’ Shield. He also had a brief stint with Inter Miami.
In 2020, the midfielder made his return to the Revolution to conclude his MLS career where it originally started. He spent 2021 playing in Vietnam before announcing his official retirement.
"It's really been hard thinking about the day I would finally hang it up because when you love something as much as I love this game, you would have had to drag me off that field," Nguyen said via his Instagram account on Friday. "But, after having time to reflect, I can finally say I'm at peace with stepping away from the game for good."
Nguyen made six appearances for the U.S. men's national team.
"I'm grateful and excited to be returning to the Washington Spirit with such a great staff and amazing group of players," Nguyen said in a statement. "I'm committed to growing the women's game in our country and I look forward to defending our title in 2022."
The Washington Spirit shocked fans by lifting the league trophy in 2021 after such a turbulent season. The club’s former coach, Richie Burke, was banned from the league after an investigation found a pattern of abusive behavior. Additionally, the team suffered a power struggle between investors that reached the pitch when players began to voice their opinions over former majority owner Steve Baldwin.
Baldwin had promised to sell his shares of the club to investor Y. Michele Kang, and in not doing so maintained the unresolved dispute.
The fight is now settled, and Y. Michele Kang is set to take over the Washington Spirit.
The NWSL's tenth season begins with the Challenge Cup on March 19.