In 1923, Inagaki's father-son performances (with his father Jiro) began to appear on the silver screen, including in such works as director Kenji MIZOGUCHI's film 'Yoru' (Night), but as time passed Inagaki set his sights on becoming a director himself, leading him to take part in Daisuke ITO's Ito Film Study Group studying scenarios.
12年、溝口健二監督の「夜」などで銀幕での親子出演を果たすが、やがて監督を志すようになり、伊藤大輔の伊藤映画研究所に参加し、シナリオを学ぶ。