President Trump will sign an executive order on Friday renaming the Department of Defense the Department of War, the White House said, fulfilling his pledge to realign the military’s mission by restoring the name the agency held until shortly after World War II.

The measure, which has been expected for some time, underscores Mr. Trump’s efforts to reshape the military to align with his goals of projecting a more aggressive image by showcasing war-fighting capabilities. Mr. Trump looks to project strength rather than the “wokeness” that he and Secretary of Defense Pete Hegseth say clouded the military’s morale and mission under former President Biden.

Mr. Trump first floated the idea in August in the Oval Office, saying it “just sounded better,” adding, “I think we’re going to have to go back to that.” He said the name change would be a reminder of the country’s record of victories in conflicts under the old name, citing World Wars I and II.

The following month, in a Truth Social post praising Mr. Hegseth, the president called him the “Secretary of War.”

The Department of Defense and the secretary of defense were named through acts of Congress, so it is unclear if Mr. Trump’s order will go into effect immediately.

During his August remarks about the potential renaming, Mr. Trump said he was confident that it would be approved.

“We’re just going to do it,” he said. “I’m sure Congress will go along if we need that. I don’t think we even need that.”