Radical left-wing activist and Congressman. Marcantonio was born in New York City on December 10, 1902. He graduated from New York University in 1925. The following year he was admitted to the bar and worked as a lawyer in New York City and served as assistant United States district attorney (1930-1931).

An active member of the Republican Party, Marcantonio was elected to Congress in 1935 from East Harlem's 20th District. An outspoken politician with left-wing views, Marcantonio was not re-selected as a candidate for the next election.

In 1938 Marcantonio stood as an American Labor Party (ALP) candidate. He won his seat back and in Congress was a strong supporter of the New Deal.

As a member of the ALP (which was heavily pushed by the Communist Party), Vito maintained an open relationship with the CP. He insisted that the Communist Party was an "American political party operating in what it considers to be the best interests of the American working class and people." When the party or individuals associated with it came under attack, no one more ardently or effectively came to their defense. He served as legal counsel for Communist and civil rights activist W.E.B. Du Bois and collaborated with Paul Robeson. This caused great anger from many people, ranging from conservative to liberal.

Marcantonio was able to overcome this opposition in large part because his Italian-American, Puerto Rican, and African-American constituents viewed as one of the few advocates of those who were not included in the American Dream. Many recalled his reaching into his pockets to help those facing eviction or in need of school clothing for their children. A Puerto Rican woman who wrote Marcantonio requesting "a small turkey for my children" stated, "You are the bread of the poor people."

During the Second World War Marcantonio played an active role in the American Committee for Russian War Relief. Along with Fiorello La Guardia, Charlie Chaplin, Wendell Willkie, Orson Welles, Rockwell Kent and Pearl Buck, Marcantonio campaigned during the summer of 1942 for the opening of a Second Front in Europe. He also was a strong opponent of US domination of Puerto Rico.

In 1945, he ran and was elected as the Congressman from New York's 18th District. In Congress he was one of the strongest opponents of Senator Joe McCarthy and the House Un-American Activities Committee (HUAC). This caused a swelling of Congressional anti-Communist "red-baiting" that still was far from effective against this strong leader of the impoverished.

New York's main parties finally decided to co-operate against this most dangerous opponent. A single candidate was run against Marcantonio, who was nominated by the Democratic, Republican, and Liberal Parties. With all their votes combined into one candidate, Marcantonio was defeated in 1950.

Marcantonio continued his law profession until his death in New York City on August 9, 1954, when upon emerging from the subway, he fell dead on Broadway at City Hall Park.

The day of his funeral the police halted traffic on First Avenue at East 115th Street to allow the assembling of a funeral procession of more than one hundred vehicles headed by fifteen coaches filled with flowers. Over twenty thousand persons passed Marcantonio's coffin. Many famous people attended the funeral, including W.E.B. Du Bois, former Minnesota governor Elmer Benson, and Communist leaders Ben Gold and John Abt. To this day, he is remembered as perhaps the most radical person ever to hold a seat in the House of Representatives.