Locascio is an interdisciplinary researcher. She worked at NIST for 31 years, rising from a research biomedical engineer to eventually leading the agencys material measurement laboratory. Locascio also served as the acting associate director for laboratory programs, the number two position at NIST, providing direction and operational guidance for NISTs lab research programs across two campuses in Gaithersburg, Maryland, and Boulder, Colorado. She received the 2017 American Chemical Society Earle B. Barnes Award for Leadership in Chemical Research Management, and the 2017 Washington Academy of Sciences Special Award in Scientific Leadership. Locascio has published 115 scientific papers and has received 12 patents in the fields of bioengineering and analytical chemistry. During her time at NIST, she received the Department of Commerce Silver Medal, American Chemical Society Division of Analytical Chemistry Arthur F. Findeis Award, the NIST Safety Award and the NIST Applied Research Award. Locascio is also a fellow of the American Chemical Society and the American Institute for Medical and Biological Engineering.
In late 2017, Locascio joined University of Marylands faculty. She was the first person to serve as the vice president for research of both the College Park and Baltimore campuses. In this role, Locascio oversaw the University of Marylands research and innovation enterprise at these two campuses, which garner a combined $1.1 billion in external research funding each year. Within Locascio's purview was the development of large interdisciplinary research programs, technology commercialization, innovation and economic development efforts, and strategic partnerships with industry, federal, academic, and nonprofit collaborators. She also served as a professor in the Fischell Department of Bioengineering at the A. James Clark School of Engineering with a secondary appointment in the department of pharmacology in the School of Medicine. In 2021, Locascio inducted as a fellow of the National Academy of Inventors. At the University of Maryland that same year, she was succeeded by interim vice president Amitabh Varshney.
On July 16, 2021, President Joe Biden nominated Locascio as the under secretary of commerce for standards and technology. She was confirmed by the Senate on April 7, 2022. On April 19, 2022, Locascio sworn in by U.S. secretary of commerce Gina Raimondo. She is the fourth Under Secretary of Commerce for Standards and Technology and 17th director of NIST. Locascio is the third female head of NIST.