Upon graduation, Elisa returned to Romania and faced difficulties finding employment due to her gender. Despite her qualifications, she encountered resistance and prejudice from potential employers.

Elisa secured a position at the Geological Institute of Romania, where she would spend most of her professional career. She started as an assistant and progressively advanced through the ranks.

Within the Geological Institute, Elisa headed various laboratories, including physics, chemistry, and microphotography. Her work involved analyzing minerals, identifying new resources, and contributing to the geological mapping of Romania.

During World War I, Elisa took on additional responsibilities related to geological surveys and resource management, playing a crucial role in supporting the war effort.

After WWI, Elisa continued her research and became a renowned expert in mineral analysis and geological mapping. She published numerous scientific papers and contributed significantly to the understanding of Romania's geological resources.

Elisa Leonida Zamfirescu retired from the Geological Institute of Romania after a long and distinguished career. However, she continued to be involved in scientific activities and mentoring young engineers.