He started as a trainee working with the co-founders Akio Morita and Masaru Ibuka and rose through the ranks as a marketing specialist.

He left Sony and enrolled in a PhD program at the Graduate Institute of International Studies in Geneva, but he did not obtain the degree.

Already perceived as the company's driving force, Idei was formally named co-CEO in 1998 and sole CEO in 1999.

On 7 March 2005, it was announced that Idei would be succeeded on 22 June by Sir Howard Stringer.

Idei founded his own consulting firm Quantum Leaps Corporation on his retirement from Sony.