President Trump personally directed an effort in February to stop Stormy Daniels from publicly describing an alleged sexual encounter with Mr. Trump, people familiar with the events say.

In a phone call, Mr. Trump instructed his then-lawyer Michael Cohen to seek a restraining order against the former adult-film actress, whose real name is Stephanie Clifford, through a confidential arbitration proceeding, one of the people said. Messrs. Trump and Cohen had learned shortly before that Ms. Clifford was considering giving a media...