WASHINGTON—Howard Lutnick’s journey from Wall Street veteran to one of President Trump’s most hawkish trade advisers began with a speech at his October campaign rally at Madison Square Garden. Lutnick extolled the virtues of tariffs and argued that the duties could at least in part replace the U.

Howard Lutnick said tariffs are essential for supporting U.S.-based manufacturing and won't trigger inflation while undergoing a Senate confirmation hearing on Wednesday.