In 1909, many ILGWU members were part of the "Uprising of 20,000," a fourteen-week strike. The ILGWU accepted a 1910 settlement that failed to recognize the union, but that did gain important working condition concessions and improvement in wages and hours.
The 1910 "Great Revolt," a strike of 60,000 cloakmakers, was led by the ILGWU. Louis Brandeis and others helped bring the strikers and manufacturers together, resulting in wage concessions by the manufacturers and another key concession: recognition of the union. Health benefits were also part of the settlement.
After the 1911 Triangle Shirtwaist Factory Fire, in which 146 died, the ILGWU lobbied for safety reforms. The union found its membership increasing.
Left-wing socialists and members of the Communist Party rose to considerable influence and power, until, in 1923, a new president, Morris Sigman, began to purge communists from union leadership positions. This led to an internal conflict, including a 1925 work stoppage. While the union leadership battled internally, the manufacturers hired gangsters to break a long 1926 general strike on the part of a New York local led by Communist Party members.
David Dubinsky followed Sigman as president. He had been an ally of Sigman's in the struggle to keep Communist Party influence out of the union's leadership. He made little progress in promoting women to leadership positions, though union membership remained overwhelmingly female. Rose Pesotta for years was the only woman on the executive board of the ILGWU.
The Great Depression and then the National Recovery Act influenced the union's strength. When the industrial (rather than craft) unions formed the CIO in 1935, the ILGWU was one of the first member unions. But though Dubinsky did not want the ILGWU to leave the AFL, the AFL expelled it. The ILGWU rejoined the AFL in 1940.
Leadership of the ILGWU, including Dubinsky and Sidney Hillman, were involved in the founding of the Labor Party. When Hillman refused to support purging communists from the Labor Party, Dubinsky, but not Hillman, left to start the Liberal Party in New York. Through Dubinsky and until he retired in 1966, the ILGWU was supportive of the Liberal Party.
In the 1970s, concerned with declining union membership and the movement of many textile jobs overseas, the ILGWU spearheaded a campaign to "Look for the Union Label."
In 1995, ILGWU merged with the Amalgamated Clothing and Textile Workers Union (ACTWU) into the Union of Needletrades, Industrial and Textile Employees (UNITE). UNITE in turn merged in 2004 with the Hotel Employees and Restaurant Employees Union (HERE) to form UNITE-HERE.