With a background as an officer in landstorm of the Swedish Army, and a determined anti-communist, he joined the White forces under Carl Gustaf Emil Mannerheim in Finland after the outbreak of the Finnish Civil War in 1918.

Oscar Ljungström had artistic interests and made several visual artworks, working mainly with oil paintings.

Theosophy made an impact on European intellectuals and artists of liberal mindset around the turn of the 20th century, and this also applied to the brothers.

Although an outspoken critic of esoterism, he advocated an eclectic ethical approach as opposed to both the state religion and secularism of his time, sparking debate on syncretism, and how Christianity could benefit from the inspiration of Eastern philosophy.

Among his last writings was Fredstankens två aspekter (1940), where he expressed hopes for a peaceful coexistence of nations after an anticipated end of World War II.