In 1933 the Amalgamated Clothing Workers of America (ACWA) began an organizing drive among New England garment workers. On April 29, 1933, Local 125 (New Haven, Connecticut and vicinity) was chartered by ACWA. Local governing bodies were established almost immediately; Shop Delegates Councils and the Executive Board each held their first meetings in May, 1933.

Local 125 worked to improve wages and hours of work, to increase job security, to provide facilities for advancing cultural, educational and recreational interests of its members and to strengthen the labor movement. A 5-day work week and "living wage" were prime objectives. Local ACWA social-athletic clubs were opened for members in 1934. Delegates received funding to attend labor conferences and speakers routinely addressed the Shop Delegates Council meetings on topics of labor interest.

Local 125 followed the industry's growth and decline. In 1933 the union represented 14 shops (over 2,000 workers); 1942: 19 shops; 1950: 24 shops; 1963: 18 shops; 1978: 8 shops. The local eventually represented shops both in Connecticut and Western Massachusetts. At various times Bridgeport, Brandford, Danbury, Derby, Manchester, New Britain, New Haven, Shelton and Wallingford shirt factories have had ACWA representation.

Key figures in Local 125 include Aldo Cursi who, with Mamie Santora, organized the Connecticut shirtworkers. Cursi served as Manager of Local 125 from 1933 until 1954. John Laurie was the local's Business Agent from 1933 until 1963. He served as Manager of Local 125 from 1954 until his death in 1964. Nick Aiello was elected Local 125's Business Agent in 1963. In 1964 he was elected Manager of Local 125.