[3][4] He was the eldest son of Miki Eikichi, a farmer, and his wife Shin, and was raised a devout Pure Land Buddhist.

Miki was in contact with over fifteen other Japanese students during his stay, including Hani Gorō, Abe Jirō, Amano Teiyū and Kuki Shūzō.

In 1924, Miki moved again to Paris, France where he studied the works of Henri Poincaré, Hippolyte Taine, Ernest Renan and Blaise Pascal.

[7] Miki became a contentious figure upon his return to Japan for his outspokenness and outgoing lifestyle,[citation needed] as well as for a controversial involvement with a widowed older woman.

[7] During this time, Miki promptly engaged with Marxist theory and developed a substantial influence over Japanese workers' movements, though did not have communist leanings.

[7] Trouble befell him when money he lent to a friend was used, unbeknown to Miki, to make illegal donations to the Japanese Communist Party.

[10] The same year, members of the Puroretaria Kagaku Kenkyūjo (Proletariat Science Research Institute), including Hattori Shisō, decried Miki's academic works after which he sought to further distance himself from Marxism.

[11] While he remained in touch with his mentor, Nishida, and other members of the Kyoto School, he worked outside mainstream academia, producing popular writings aimed at a wide audience.

[12] His firm belief that philosophy should lead politics encouraged the political activism of fellow intellectuals, and when offered in 1937,[under discussion] he eagerly accepted the opportunity to head the cultural division of the Shōwa Kenkyūkai (Shōwa Research Association), the brain trust of Prince Konoe Fumimaro's Shintaisei (New Order Movement).

During this time Miki conceptualized the Greater East Asian Co-Prosperity Sphere though felt deeply betrayed by the Imperial Japanese Army's misuse of the doctrine, employing it in justifying aggressive expansion in China and Southeast Asia.

[17] His conception of tradition as active, ongoing transmission by human action he contrasts with the immanent evolutionism of Hegelians and conservative traditionalists.

[5] In response to the growing labour movements in Japan during the late 1920s, Miki published three successive books on the subject of Marxism: Modern Consciousness and the Materialist View of History (1928), Preliminary Idea of Social Science (1929), and Idealist Theory of Form (1931).

[4] Kenn Nakata Steffensen suggests that to consider Miki's work as either fascist or Marxist is incorrect, stating that it stands in critique of liberalism, Marxism, nationalism and idealism.

[15] Miki developed a reading of Heidegger's early philosophy as essentially being in the tradition of Christian individualism, reaching back to Saint Augustine and being fundamentally anti-Greek in character.