Junro Ito flew to California this year on a mission: The billionaire executive at Seven & i Holdings, the Japanese parent company of 7-Eleven, felt the company had lost its way. He wanted to revive the culture fostered by his father, the company’s founder.

Mr. Ito wanted to establish training workshops for Seven & i employees and was seeking advice from experts at Claremont Graduate University, where the management guru Peter Drucker, a close friend and adviser to his father, had taught for decades.

The workshops would instill in executives and others at Seven & i the philosophy espoused by Mr. Drucker — that the purpose of a company is to serve its customers, not to maximize profits for shareholders.

Back in Tokyo, the company started hosting the monthly management workshops just as Mr. Ito, a vice president at Seven & i, began plotting a multibillion-dollar takeover. His family owns a minority stake in Seven & i, and he wanted to keep it from being acquired by a foreign rival.

Seven & i has more than 85,000 stores, and 7-Eleven is a cornerstone of Japanese society. People who know Mr. Ito, speaking on the condition of anonymity, said his fixation on Mr. Drucker offered a window into his plan for the company.