Wing Fong Chin quickly learned how to produce garment pieces at an efficient rate and was welcome at all the garment shops in Chinatown. Because Chin, like many workers, moved from shop to shop for higher piece rates, her face became familiar to both factory owners and representatives of the International Ladies Garment Workers Union ("ILGWU") which was attempting to unionize the garment shops in Chinatown.

Unlike most Chinese immigrant women who worked in the Chinatown garment industry, however, Chin had a father who was an English instructor. When union organizers learned that she could understand and speak English, they asked her if she would serve as an interpreter between union officials and Chinese-speaking workers. Up until that time, union organizers had experienced communication difficulties conveying the benefits of joining the union to many workers. Chin agreed to the request and served as an interpreter for union organizers whenever they visited any shop where she was working. Soon thereafter, union organizers asked Chin to serve as shop steward for the shops where she was working. In 1957, Chin became a member of ILGWU Local 25.

The ILGWU was instrumental in reducing work hours, increasing wages, establishing a day-care center for the children of garment workers, and obtaining health coverage and pensions for garment workers. After joining the ILGWU, Wing Fong Chin participated in many facets of her local. In addition to the grievance committee, she served on the membership committee, orientation committee, and education committee. She helped with voter registration, distributed union leaflets, attended observances such as the annual March 25 ceremony to remember the 1911 Triangle Shirtwaist Factory fire that killed 146 female employees, and collected union dues from members in her shop and delivered the dues to the local office.

In recognition of her active involvement in union activities, the ILGWU arranged for Chin to attend various education, labor, and leadership seminars to enhance her union skills.

In 1965, the ILGWU named Chin to the Executive Board of Local 23-25. Locals 23 and 25 had merged a few years earlier. In 1971, Chin represented Local 23-25 for the first time at the 34th ILGWU National Convention in Miami Beach, Florida. Convention delegates met every three years in Miami to elect union officials and discuss union contracts. Chin represented her local at every succeeding convention until her retirement from the Executive Board. Chin's work with the union was beneficial for union organizers and fellow workers. Union work also provided her with personal fulfillment.

"I think [my mother's] involvement in the union is not just [for fellow] workers but for herself, not just for the improvement of working conditions, but for herself it's a learning of the American experience."