In 1946, von Dassanowsky made her opera debut as Susanna in Mozart's The Marriage of Figaro at the Stadttheater St. Pölten and created in concerts for the Allied High Command.

With senior partners August Diglas and Emmerich Hanus, the studio created such German-language classics as Die Glücksmühle (The Mill of Happiness, 1946), Dr. Rosin (1949), and Märchen vom Glück (Kiss Me, Casanova, 1949), and gave Gunther Philipp and Nadja Tiller their first screen roles.

Dassanowsky starred in operas, operettas, theatrical dramas and comedies, helped initiate several theater groups, was announcer for Allied Forces Broadcasting and the BBC, toured West Germany in a one-woman-show and gave master classes in voice and piano.

During this period, Dassanowsky also modeled exclusively for famous Austrian painter Franz Xaver Wolf (1896 – 1990), whose work featuring her image is now in museum and private collections.

She was executive producer of the award-winning dramatic short film, Semmelweis (2001), the spy-comedy, Wilson Chance (2005), and several works in progress at the time of her death, including the documentary Felix Austria!

The first phase of this project was complete in late January 2009, when the Elfi von Dassanowsky Fund initiated its program of charitable contributions to non-profit organizations in the U.S. and Europe.

The first Elfi von Dassanowsky Prize for work by female filmmakers was presented to Norwegian artist Inger Lise Hansen for Parallax (2009) at the Vienna Independent Shorts Film Festival in June 2010.