Leslie Wexner was among the pathfinders for American business in China in the 1970s, shunning the official channels in Beijing for Shanghai, making big investments on essentially a handshake.

“I just met a businessman somewhere, and he trusted me, and I trusted him, and we started doing things,” Mr. Wexner, the 81-year-old founder of L Brands Inc., said in a talk at Harvard’s Center for Public Leadership.

If...