WASHINGTON—Howard Lutnick’s journey from Wall Street veteran to one of President Trump’s most hawkish trade advisers began with a speech at an October campaign rally at Madison Square Garden.

Howard Lutnick, President Donald Trump’s nominee to lead the Commerce Department, offered a detailed defense of tariffs in his confirmation hearing, the clearest signal yet from a cabinet pick that the new administration is prepared to impose the levies on allies and adversaries alike.

President Donald Trump’s nominee to lead the Commerce Department, Howard Lutnick, told senators the argument that tariffs cause inflation is "nonsense" during a confirmation hearing.