President-elect Donald Trump marches toward his Jan. 20 inauguration with nearly seven in 10 American adults convinced he is the change agent he promised, but with the public divided over the kind of transformation he may bring to the federal government.

A new Wall Street Journal/NBC News poll finds that 68% of Americans believe Mr. Trump will change the way business is conducted in Washington. But one-third of that group—or about 20% of all adults—believe it will be the wrong kind of change.

Including...