BEIJING — He was a brilliant student during the dark days of China’s Cultural Revolution. He visited America, and left unimpressed with democracy. Plucked from academia, he climbed the ladder of Beijing’s brutal politics.

He did not attend President Trump’s meeting with Xi Jinping last week, but his ideas and advice almost certainly helped shape it: Few in the Communist leadership have pressed China’s effort to surpass the United States for as long as Wang Huning, a shrewd strategist who has served three Chinese presidents from behind the scenes.

As Mr. Trump pits his advisers against one another and sows doubt about America’s future in Asia, Mr. Wang has emerged as one of Mr. Xi’s most influential confidants, one who has brought a steadiness of vision and purpose to China’s rivalry with the United States.

A college professor turned party theoretician, Mr. Wang, 63, has long argued that China needs a strong, authoritarian state to restore it to national greatness after a century of humiliation by foreign powers. He has helped cast Mr. Xi as leading China into a “new era” of global ascendance by keeping society under the party’s tight control.