The role of anarchists and what could be called protosocialists dates back to the Guilded Age and arguably Reconstruction in American History. The Knights of Labor were one of the early unions dating back to the 1870's. Similar to other vague union groups of the era such as the Irish Molly Maguires, the K of L behaved somewhat like a blend of a union, secret society, and organized crime syndicate and was treated as such by the US government. While many members of the K of L rejected radical ideals, events such as the Haymarket Affair portrayed them as extremist anarchists. The event itself consisted of a K of L organized strike in which anarchists had a heavy presence and a bomb was thrown from an unidentified source at a cluster of policemen. 8 Anarchists were tried following the event and this saw the decline of the K of L's prominence in labor. Due to the Haymarket Affair and other such events, the public saw organized labor in a very negative light up until The Progressive Era and the First World War when the AFL grew and received wartime support.

Famous American Socialist politician and author Eugene V. Debs was an incredibly influential socialist who helped to organize multiple strikes during the Guilded Age such as the Pullman Strike. He influenced many socialists, anarchists, and radicals of the era and ran for president on multiple occasions. He is widely regarded to be one of the more successful socialists in US history mostly due to his role occurring before the first red scare during WWI (during which he was imprisoned under the new Sedition Act of 1917 which aimed to silence those that spoke out against the war.)