He attended the Provincial Secondary School (Landesrealschule) in Krems an der Donau and did military service during World War I.
As a director Emo contributed much to the popularity of actors such as Paul Hörbiger, Theo Lingen and above all Hans Moser, who appeared in 21 of his films altogether.
In 1936 Emo founded in Berlin, with Paul Hörbiger and the Austrian consul Karl Künzel, the Algefa-Film company.
During the time of National Socialist government, he was reckoned one the principal directors of Wien-Film, where he continued to make light comedies, often with Moser, to whom he allowed a great deal of latitude for improvisation.
Emo's only expressly propagandist film was Wien 1910 (1943), which was made with the intention, through its distorted representation of the politics of Vienna around the anti-Semitic Karl Lueger and the German nationalist Georg Ritter von Schönerer, of legitimizing the Anschluss of Austria by Germany.