Although leaning towards left-wing politics already at Tokyo University, where he joined a Communist student group, Imai's directing career, after serving as continuity writer at J.O.

[5] While his 1950 drama Until We Meet Again portrayed a young couple's doomed love against the backdrop of the Pacific War, the 1953 anti-war film Tower of Lilies was a stark account of untrained female students forced into aiding military troops during the final stage of the Battle of Okinawa.

Other films addressed the present-day struggles of day labourers (And Yet We Live), troubled youths (Jun'ai monogatari), poor farmers (The Rice People) and children of interracial relationships (Kiku to Isamu).

[6] While film historians acknowledge Imai's solid directorial skills, the lack of a consistent style, and tendency to focus more on consequences than analysis of his themes, have been recurring subjects of criticism.

[8] Imai won the Blue Ribbon Award for Best Director four times: 1950 for Until We Meet Again,[9] 1953 for Tower of Lilies and An Inlet of Muddy Water,[10] 1956 for Mahiru no ankoku[11] and 1957 for Jun'ai monogatari and The Rice People.