Daisaku Ikeda was born in Tokyo on January 2, 1928, the fifth of eight children, to a family of seaweed farmers. As a teenager he lived through the Second World War, and its senseless horror left an indelible mark on his life. His four older brothers were drafted into military service ; the eldest was killed in action. These experiences, along with the human anguish and turmoil he witnessed in the years following the war, continue to fuel his lifelong quest to root out the fundamental causes of human conflict and suffering.
In 1947, at the age of nineteen, he met Josei Toda (1900-58), second president of the Soka Gakkai, a lay Buddhist society whose activities are based on the philosophy of the 13th century Buddhist teacher and reformer Nichiren. Ikeda found in Toda a completely open and unaffected man, a person of unshakable conviction with a unique gift for explaining profound Buddhist concepts in logical, accessible terms. Ikeda, who from his youth was an avid reader of poetry, literature and philosophy, displayed an insatiable thirst for knowledge. Amidst poverty and ill health, he continued his studies under the tutelage of educator and publisher Toda, whom he regards as his lifelong mentor.

Through his relationship with Toda, Ikeda came to understand and respect the Soka Gakkai's philosophy as a concrete means to realize the universal values of human dignity and peace. Toda, together with Soka Gakkai founder and first president Tsunesaburo Makiguchi (1871-1944), had been jailed in 1943 for refusing to compromise their religious beliefs in support of the Japanese war effort. Makiguchi died in prison at the age of 73. Toda emerged from the ordeal of imprisonment just prior to Japan's surrender and dedicated the remainder of his life to the reconstruction and development of the Soka Gakkai.