For 14 generations his family had owned a sake brewery, so there was little doubt that Akio Morita, born in 1921 in Nagoya, Japan, would, as the eldest son, run the business one day. But when young Akio was in junior high school, his family bought a phonograph, and he was entranced—not with the music but with the electronics. The discovery changed his life—and eventually changed the way we listen to music.

By introducing the Sony Walkman 20 years ago, Morita, who died of pneumonia in Tokyo last week at age 78, freed us from the tyranny of other people's boom boxes, allowing us to live in our personal musical cocoons. He got the idea after seeing Masaru Ibuka, with whom he founded Sony in 1946, using headphones to listen to a tape recorder.

Japan was reeling from its World War II defeat when Ibuka invited his old Imperial Navy comrade to join the fledgling electronics company that they would name Sony. Morita went along—after getting his father's permission to abandon his future in the sake business. Sony's first breakthrough came in 1955, when the company developed the first near-pocket-size radio. (To show it off, Sony salesmen wore shirts with slightly larger-than-normal pockets.)

Later, Sony introduced the Trinitron, which was the first reliable color TV, the ill-fated Betamax VCR and the popular PlayStation, among a host of consumer electronics devices. Despite his enormous success, Morita, who had three children with his wife, Yoshiko, lived modestly. "He never wore a Rolex," says William Ouchi, a professor of management at UCLA. "He lived in a comfortable home, not a mansion, but he had a touch for technology—a huge loudspeaker installed in his living room. He wanted to see the possibilities."