WASHINGTON — Stephen K. Bannon has held court in the Capitol Hill townhouse of Breitbart Media since he packed up his West Wing office last month, meeting with conservative lawmakers, advocating hard-line policies on undocumented immigrants and waging gleeful war on those he considers traitors to the Trump cause.

Now Mr. Bannon is taking his insurgency abroad.

Next week, he plans to travel to Hong Kong to deliver a keynote address at an investor conference, where he will articulate his call for a much tougher American policy toward China. CLSA, the Hong Kong brokerage firm that invited Mr. Bannon, is owned by a politically connected Chinese investment bank, Citic Securities.

People close to Mr. Bannon said he met recently with Henry A. Kissinger, the elder statesman who opened a diplomatic channel to China in 1972, to exchange views about the relationship with Beijing. Mr. Bannon said he admires Mr. Kissinger and has read all his books, but none of that swayed him from his preference for confrontation over diplomacy.

The meeting and speech kicks off an effort by Mr. Bannon, who served as President Trump’s chief strategist, to influence his former boss on China policy as much as he does on immigration, trade or tax policy. Given the lack of strong voices on China in the administration and the inconsistency in its approach, Mr. Bannon believes he can make a difference, though his record when he was inside the White House was mixed.