Son was a third-generation Korean with Japanese citizenship. Before traveling to the United States to study in 1973, he repeatedly tried to meet Fujita Den, president of McDonald’s Company (Japan), Ltd., to seek his advice. When they finally met, Fujita advised Son to study computer science. Nearly 20 years later the two met again. By that time, Son had become a leading distributor of computer software and related publications in Japan and was president of Softbank Corp. Fujita was deeply moved when Son thanked him for the advice he had given years earlier. Son graduated from the University of California, Berkeley, in 1980 with a B.A. in economics. While in school, he and a group of other students developed a sound-translation device capable of converting Japanese into English and German. He sold the technology to Sharp Corporation and used the proceeds to establish the predecessor to Softbank after his return to Japan in 1981.

In 1997 Softbank began investing in various global Internet initiatives. Despite losing an estimated 75 billion yen ($748 million) in the dot-com crash of 2000, Son established a broadband service with Yahoo Japan Corporation the following year. In 2006 Son engineered Softbank’s acquisition of Vodafone KK, the Japanese arm of the mobile-phone group Vodafone.