The good-natured Zhang, who grew up in rural poverty, earns so little from the sport that he has taken on an array of menial jobs to keep his boxing dream alive.
He was a security guard but was fired after a few days because he was deemed too small. He also previously worked in a restaurant kitchen, in home removals and construction.
His job as a delivery driver, first in the city of Kunming and now in the capital Beijing, comes with its own challenges.
Zhang’s electric scooter — bought for 6,000 yuan ($870) thanks to a small loan — was stolen while he was delivering a meal.
“I chased the person wildly for more than two kilometres but I couldn’t catch up with him,” he said in an interview at Beijing’s M23 Boxing Club, home to WBA featherweight world champion Xu Can.
“A delivery person always protects his meal, no matter what,” Zhang said, adding that he held on to the takeaway even while chasing the thief.