Nippon Steel Corp. won conditional US approval for its $14.1 billion purchase of United States Steel Corp., capping a lengthy saga in a tie-up that will create one of the world’s largest steel companies.

U.S. Steel and Nippon Steel announced on Friday that they had entered into an agreement with the U.S. government to seal the terms of a “partnership” between the companies, more than a year after the...

Trump said Thursday that he would as president have “total control” of what U.S. Steel did as part of the investment.