In her early years as an artist, she was known for her woodcuts, which were a modification of the expressionistic xylographic tradition, thus being one of only few women of her time leaving a distinctive print-graphic work.
Later on, she found her vocation in glass painting, creating windows for many houses of worship in Austria, in several European countries, even in the Middle East and in Asia, as well as in the USA.
Her numerous stays at the Schlierbach Monastery were particularly creative and fruitful in the life of Margret Bilger. She developed a deep friendship with Father Petrus who was in charge of the glassworks studio. The bucolic surroundings of Schlierbach were her artistic inspiration and sanctuary. She participated in several competitions and exhibitions and earned many awards.
In the 1950s, Margret Bilger reached the peak of her worldwide recognition.
In the 1960s, she created textile works, reverse glass paintings, watercolor paintings and drawings.

Margret Bilger had a great influence on the development of stained glass, and particularly her work created in Schlierbach has worldwide recognition.