So the slaves were freed in 1865... what happened next? How did they go from having absolutely nothing to becoming an essential aspect of Americans 150 years later? How'd they do it? I would target 1865-1965, because Dr. King made the next to last step for the black man and Obama made the final step into Presidency. But how did blacks in 1865 survive???
A lot of them became sharecroppers with their former owners. Others took advantage of the Homestead Act and bought farms out west. Many had marketable skills like blacksmith or carpenter and were able to support themselves. In cities they all moved into the same neighborhoods and sustained each other's businesses. Before the minimum wage laws they often worked for less than whites would. If they were lucky enough to work in a union shop they got paid enough to live on. Many people broke into professions by serving apprenticeships back then, so blacks with skills would hire black apprentices. This included doctors. Someone had to work in black only hospitals. Blacks could also teach in black schools. Martin Luther King Sr.'s teacher had only a third grade education. Rich people had lots of servants then and blacks were popular choices. Only a handful of Black Americans became famous. One sad case was a heart surgeon who ended up dying because when he had a heart attack the white hospital wouldn't take him. He died en route to the black hospital.