Mr. Smith, who is about 40, was removed in 2014 from J&J Cafeteria after a resident notified the authorities of the abuse.

“It is almost inconceivable that instances of forced labor endure in this country to this day, a century and a half after the Emancipation Proclamation,” said Assistant Attorney General Eric Dreiband of the Civil Rights Division. He added that the department would continue to investigate and prosecute human traffickers involved in forced labor.

Mr. Smith said in a statement that was read at the sentencing hearing, “Today, I feel free — out of the prison Bobby had me in.”

He added that he had hoped to open a restaurant one day. “It would be a place where all people of every kind would be welcome,” Mr. Smith’s statement said. “My workers would be nice and greet everyone with kindness. It would be a bright and happy place for everyone.”

The abuse against Mr. Smith took place from 2009 to 2014, and often occurred when he made a mistake or did not work as quickly as Mr. Edwards expected, prosecutors said.