Born on January 21, 1932, the second son of the printing-business man Inamori Kesaichi in Yakushi-cho, Kagoshima. In childhood he suffered from tuberculosis and questioned the meaning of life while reading the religious book 'Seimei no Jisso' (The True Reality of Life). He graduated from the Faculty of Engineering of Kagoshima University (1955) and entered Shofu Industry, a Kyoto insulator maker, but the company was on the verge of bankruptcy with delayed wages, and he decided to leave after a clash with his boss. On April 1, 1959, at 27, with seven people including his former boss Aoyama Masaji, he founded 'Kyoto Ceramic Corporation' (today Kyocera) in Nakagyo Ward, Kyoto, with capital of 3 million yen, entering the electronic components market with fine ceramics technology. He developed his original management method known as 'amoeba management,' in which all employees were divided into small groups each managing on independent accounts, and grew rapidly. In 1984, seizing on the liberalization of the telecommunications business, he founded Daini Denden Planning (DDI, today KDDI), and at 54 challenged the telecommunications market monopolized by NTT. In 2000 with the merger of DDI, KDD, and IDO, KDDI was born, and grew into Japan's second-largest telecom company. In 1985 he invested 20 billion yen of his private funds to found the Inamori Foundation, and established the 'Kyoto Prize,' a world-class scientific prize (honoring pioneers in Nobel Prize-class fields). In 1984 he founded 'Seiwajuku' and continued management guidance for young managers without compensation for 30 years. In January 2010, at the request of the Hatoyama Yukio Democratic Party government, he took office without compensation as chairman of the collapsed Japan Airlines (JAL), at 78 beginning a second management career. While laying off 16,000 of all employees, he introduced 'amoeba management,' achieved operating profit of 204.9 billion yen (an all-time high) in the term ending March 2012, and realized the miraculous rebuilding of re-listing JAL in September 2012. He died of senile decay in Kyoto on August 24, 2022, at 90.

A philosopher-type manager with a religious view of life. Through his youthful experience with tuberculosis and his encounter with 'Seimei no Jisso,' he gained the belief that 'life is a place to polish the soul,' and in later years he entered the Buddhist priesthood (tokudo) as a layman (1997). The philosophy of 'altruistic management' — with the starting points 'Is the motive good? Is there no private interest?' and 'Pursue what is right as a human being' — influenced many managers. Preferring a plain life, for many years after founding Kyocera he ate in the employee cafeteria. In guidance of young managers at Seiwajuku he gave passionate, sermon-like talks and was admired as 'Inamori sensei.'

Kyocera is one of the world's largest makers of ceramic electronic components, and KDDI, the second-largest telecom in Japan, continues to grow, while the 'amoeba management' left by Inamori has been introduced at companies around the world, starting with Toyota and SoftBank. The rebuilding of JAL (2010-2012) has also become a Harvard University case study as a successful model of Japanese corporate revival. The Inamori Foundation's 'Kyoto Prize' (in the four fields of thought, art, basic science, and advanced technology, with a prize of 100 million yen each) is called 'Japan's Nobel Prize,' and has honored Yamanaka Shinya (iPS cells) and Honjo Tasuku (PD-1, later a Nobel laureate) ahead of other prizes. Seiwajuku (closed in 2019, with some 15,000 participants worldwide) — whose students also included such managers representing Japan as Son Masayoshi and Yanai Tadashi (Uniqlo) — had a great influence on the Japanese economy. His books 'A Compass to Fulfillment' and 'The Work Way' have been translated worldwide, and in China in particular have been huge bestsellers exceeding 20 million copies.