The National Labor Relations Board found that the hotel at 636 S. Michigan unlawfully fired workers and cut healthcare benefits.
The board also ruled the hotel acted improperly by asking employees to sign a petition to decertify the union.
Thursday, leaders of UNITE HERE Local 1 said it would be morally wrong for the hotel to appeal the ruling.
Two workers who lost their jobs reacted to the ruling.
"I just want a better future for my family. And all I ask is that we be treated fairly and as human beings," said Renee Walker.
"It came with no warning. It came with no care about our futures," said LaMar Johnson.
No one from the hotel could be reached for comment.