She plays for Pyongyang City Sports Club and the North Korea women's national football team as a forward.
[1][2] At the 2017 AFC U-19 Women's Championship, Sung was named the tournament's Most Valuable Player and earned the Golden Ball for most goals scored.
[3] In 2016, she was part of North Korea's 2016 FIFA U-17 Women's World Cup squad, where she was awarded the Silver Ball for her performance.
[5] Later that year, she was part of North Korea's 2016 FIFA U-20 Women's World Cup team and came on as a substitute in the final against France.
[7] In 2017, Sung made her senior debut for the North Korea women's national football team against China and scored a goal after coming on as a substitute.