Sampson was one of eight children and was born in a black family[1] in Pittsburgh, Pennsylvania, U.S. to Louis Spurlock and Elizabeth A.

[2] She left school at 14 due to family financial difficulties and found work cleaning and deboning fish at a market.

After she received the highest grade in a criminology course, George Kirchwey of Columbia, one of her instructors, encouraged her to become an attorney.

[1] She married Rufus Sampson and they moved to Chicago where while working full-time during the day as a social worker she studied law at night.

Sampson graduated from John Marshall Law School in 1925 winning a special dean's commendation for ranking at the top of her jurisprudence class.

[3] In 1924, Sampson opened a law office on the South Side of Chicago, serving the local black community.

In these meetings, Sampson sought to counter the propaganda in the Soviet Union during the Cold War regarding the treatment of African Americans in the United States.

And the record shows that the Negro has advanced further in this period than any similar group in the entire world.

Supreme Court Justice William O. Douglas said that her actions "created more good will and understanding in India than any other single act by any American".

Most of the cases that she heard were housing disputes involving poor tenants, in which she was perceived as "an understanding but tough grandmother".

Sampson's great-niece, Lynne Moody, is an actress who appeared in the television miniseries Roots.