SHANGHAI—At home and abroad, the swaggering Lu Wei, China’s now disgraced chief censor, won all his battles.

Humiliation was his trademark, whether publicly cowing the country’s “Big V” bloggers—wits and satirists who once commanded tens of millions of followers with mild critiques of the regime—or extracting homage from Western media and technology executives. On a visit to Silicon Valley three years ago, he famously took a spin in the office chair of Facebook founder Mark Zuckerberg.

That...