A key figure in the United States' 2019 World Cup win and their 2024 Olympic triumph, Dunn hoisted the championship trophy in the top-flight NWSL three times, with the North Carolina Courage in 2018 and 2019 and with the Portland Thorns in 2022.
A versatile talent who was lethal in the midfield and forward positions, she became a critical piece of the national team's defence, shining at left back despite it not being her preferred role.
"I leave the game with a sense of peace and deep fulfilment for all that I’ve accomplished,” Dunn said in a statement.
"I’m grateful for the incredible people I’ve had the privilege to work with, from teammates and coaches to family and friends, and all the amazing moments we’ve shared. I’m very much looking forward to my next chapter ahead."
Dunn is the latest in a series of high-profile players from the United States' modern golden age to retire. She played alongside the likes of Megan Rapinoe and Alex Morgan, cementing herself as a bedrock of the U.S. backline.
Among the first Black stars to break through in a once overwhelmingly white US women's soccer programme, Dunn served as a role model for the next generation.
"I first kicked a soccer ball at the age of four, never knowing it would change my life," said Dunn. "My journey wasn’t perfect, but it was beautiful."