Final answer:
Dred Scott was the enslaved man who sued for his freedom in the Supreme Court. The court's ruling in the case of Dred Scott v. Sandford had significant implications for the status of Black people, citizenship, and the spread of slavery in American territories.
Step-by-step explanation:
The enslaved man who sued for his freedom in the Supreme Court was Dred Scott. In the case of Dred Scott v. Sandford in 1857, the Supreme Court decided that Scott remained enslaved and could not sue for his freedom because he was not considered a United States citizen. This decision also ruled that Black people could never be citizens and that Congress had no authority to stop or limit the spread of slavery into American territories. The court's ruling made the Missouri Compromise unconstitutional and undermined the idea of popular sovereignty.