The market revolution greatly impacted American immigration and transformed the working class. This was the birth of wide-spread factory labor in the United States. Previously, most Americans lived and worked on farms. More people had to work in factories, so people from the countryside were encouraged to come to cities and mill towns for jobs. They left subsistence farming and a barter economy for a more capitalist lifestyle. For the first time in the country's history, large amounts of people began working for wages. They became part of an economic hierarchy with bosses and employees. This migration gave birth to the new working class. In this system, people had less control over the conditions of their daily lives. Their work hours, conditions, and even housing were now dictated by the industry they worked in and the company they worked for.

Factories needed cheap and unskilled labor to fill jobs under this new system. At first, young women often filled these roles. However, as industrialization grew, factory owners looked to immigrants. Fortunately for them, this was a period of massive immigration. Over one million Irish, fleeing poverty and the potato famine, were coming to the country in the late 1840s. There were also many German immigrants at this time. Immigrants were often desperate for jobs and had few other options than factory work in their new country. Therefore, they made up a significant amount of the working class.