She was one of the main proponents of the silent march campaign, Stay Where You Are, that originated in an announcement made during the Sinking of MV Sewol in 2014.

Since the birth of her child, Yong had been on maternity leave from Parliament; temporarily substituted while in absence by Basic Income Party leader Shin Ji-hye.

On 5 May 2023, the Children's Day of South Korea, she delivered a speech with her two-year-old son, advocating for the elimination of no kid zones.

[6] She worked as a special committee member for the investigation into the incident and her findings served as a major basis for the impeachment of the responsible minister.

Yong Hye-In has been described as someone who is a "vocal supporter of the rights of women, children, working-class people, and other politically underrepresented groups".