It is often noted that former US President Donald Trump brought unpredictability to Washington’s relationship with China. This may appear intuitively true, but in what ways was Trump actually ‘unpredictable’ towards China? We show that the most unpredictable feature of Trump’s approach was his rhetoric, strongly defined by impulsivity, emotion and provocation. This generated rhetorical unpredictability which was regularly seen in inconsistent and contradictory statements. Using political psychology and leadership personality approaches, we further demonstrate that this unpredictable rhetoric can be traced to Trump’s psychological profile. We argue that while the composition of Trump’s China rhetoric was often difficult to anticipate, as a component of his US China policy it was predictable to the extent that it was grounded in his personality. Trumpian China policy broadly followed longer-term trends, but the president’s erratic rhetoric had domestic and international consequences for the relationship. The article further contributes to work on unpredictability in international relations (IR), and on leadership personalities and foreign policy.