HONG KONG — At his peak, Jia Yueting was among the brashest and most flamboyant figures on China’s frenzied technology scene. He charged into businesses as varied as smartphones, electric cars and sports broadcasting, vowing to challenge giants like Apple and Tesla.

Now, Mr. Jia is the highest-profile name on something else in China: an official online blacklist of credit defaulters. Being on the list means he can be blocked from flights and high-speed trains and even from making big purchases.

The publicly searchable database, maintained by China’s top court, is part of a growing effort by officials to rein in irresponsible borrowing — including by naming and shaming.

Mr. Jia was added to the blacklist this week over unpaid debt totaling $72 million, including interest and fees, that he owed to Ping An Securities, a brokerage. Two units of LeEco, the group of companies that Mr. Jia controls, had already been blacklisted for smaller unpaid amounts. LeEco’s ambitious, debt-driven expansion began running aground last year, causing angry creditors to stage sit-ins at the company’s Beijing office and leading courts to take action.