The Polish American Congress was established in response to the threat to Poland’s freedom caused by German and Soviet aggression in September 1939 and to express in one voice; support for the restoration of a free and sovereign Poland once the war was won. The Congress of Polonia met in Buffalo, New York, from May 28 to June 1, 1944. Composed of roughly 2,600 delegates representing Polish and Polish-American organizations, the Congress created the PAC, defining its goal of a free Poland and underscoring its support for the US war effort against the Axis powers.

The PAC was the first umbrella organization representing a majority of Polish-Americans, who had been represented by a wide range of smaller, mostly local organizations. Creation of PAC was enthusiastically welcomed by most of the Polish-American community. Shortly after its creation, it boasted 6 million members and followers.

The Congress elected Karol Rozmarek as the first president of the PAC. He was succeeded in 1968 by Aloysius Mazewski, who served until his death in 1988. Under Mazewski, Leonard F. Walentynowicz served as executive director of the PAC for a number of years. Edward Moskal was elected president in 1988, and he, too, served as president for the remainder of his life. Its current president is Hubert J. Cioromski.