Obayashi was born on 9 January 1938 in the city of Onomichi, Japan. He was the eldest son of a father who was one in a long paternal line of medical doctors. As his father was called to the battlefront during World War II, he was raised in his early infancy by his maternal grandparents. Through his childhood and adolescence Obayashi followed many artistic pursuits including drawing, writing, playing the piano, and a growing interest in animation and film.