In 1938, Eleonora received a stipend from Lithuania's Ministry of Education to study doll making in Czechoslovakia. The same year she participated in the International Art Exhibition in Berlin and in the 20th Anniversary of Lithuanian Independence Art Exhibit in Kaunas. She also started work at the Kaunas School of Applied Arts as a teacher of ceramics and taught there until 1944. In December of 1938, Eleonora married Aleksandras Marciulionis, a sculptor and fellow teacher at the Kaunas School of Applied Arts. In 1939, Eleonora's works were shown at the Internation Art Exhibition in New York.

In 1946, Eleonora was invited to organize a department of ceramics at the School of Applied Arts in Freiburg, West Germany, where she taught ceramic arts until 1949. While teaching, she continued creating her own decorative vases. The governing board of the Lithuanian Community in Germany chose one of her vases to present to Queen Elizabeth II of England on the occasion of her wedding. Also, the Lithuanian Red Cross commissioned a large decorative vase as a gift for Cardinal Stritch of Chicago.

In 1949, the Marciulionis family moved to Adelaide, Australia. Here, they lived in a small cottage in the Eden Hills with a great view of the ocean. For Eleonora's art the conditions were very difficult - she was busy raising a family and there was no room for a studio and a kiln. To get her clay creations to a kiln, she had to travel by train. Jolts and vibrations on the train damaged the brittle dry clay structures. The type of work she wanted to do was impossible.

In February of 1956, the Marciulionis family relocated to the United States and settled in Chicago. Soon after her arrival, Eleonora created the Stations of the Cross (14 panels about 2 ft. wide and 1 ft. high) for the chapel of the Marion Monastery in Chicago in 1957. She created another set of Stations of the Cross for the Jesuit chapel next to the Lithuanian Youth Center in Chicago. Now, Eleonora's creative output exploded. She not only created decorative vases, but also candleholders, plates, birds, flowers, graceful and whimsical figurines, Madonnas, angels, and all types of natural and mythical creatures. Her imagination and her control of her difficult medium did not seem to have limits. The solo exhibitions of her work are evidence of her astonishing productivity: 52 new works were exhibited in 1970, 95 - in 1974, 52 - in 1980, and more than 50 - in 1988.

Eleonora was a master of her medium and has described her creative process somewhat as follows. First a spontaneous vision appears in her head. There are elements in the vision that present a technical challenge never before achieved with her previous works. She becomes obsessed by the challenge, incessantly trying to come up with the solution. Relief comes only after the solution is successfully implemented. Implementation is not always straight forward, however. The peculiarities of her medium require her to improvise. The complex forms that Eleonora produced often required that the firing of the clay be done in parts. Even then the brittle dry clay structures could not be moved without supports and, therefore, Eleonora routinely disassembled her kiln and reassembled it again around her structures prior to firing. The overall work of art was then glued together and glazed.

In 1998, in recognition for her life's achievements in ceramic art, Eleonora Marciulionis was awarded a prize by the Cultural Council of the Lithuanian-American Community. Eleonora Marciulionis died on December 18, 2001, in Chicago.