The American Labor Party was formed on 7/22/1936 [NYT 7/23/1936] by "conservative" Socialists who had separated from the Socialist Party, liberal Republicans, and union leaders. It collected several proto-political groups who had been looking at a new labor party. Among its leaders were David Dubinsky of the International Ladies Garment Workers Union and Sidney Hillman of the Amalgamated Clothing Workers Union. An original impetus for the creation of the party was to provide a means for supporters of the New Deal to vote for FDR without voting Democratic (particularly disaffected Republicans).
In 1938, Vito Marcantonio was elected to Congress where he represented East Harlem's 20th District. Marcantonio was the most popular leader of the party throughout its existence. He was later joined in the US House by Leo Isacson.
During the 1930s, the ALP was the major left-leaning anti-Tammany force in New York City and was a supporter of Mayor LaGuardia. The party suffered a major setback when the more moderate faction separated in 1944 to form the Liberal Party.
By 1946, the ALP was becoming too closely identified with the Communist Party. Both the Democrats and the Republicans, who had not shunned the ALP earlier, began to take action to marginalize the ALP. In the 1948 presidential elections the American Labor Party gave its support to Henry Wallace and the Progressive Party.
Both Leo Isacson (1948) and Vito Marcantonio (1950) lost their seats in Congress. Marcantonio left the party in 1953, saying that it was moving towards becoming a political interest group rather than a political party.
On 10/2/1956, the ALP state committee voted unanimously to disband. The party lost its ballot status in 1954 when its candidate for governor, John McManus, failed to garner 50,000 votes, and declining interest made it nearly impossible to collect the requisite number of signatures for the election of 1956 [NYT 10/8/1956].