Her pioneering research brought her international repute. She co-authored a range of standard works in the field of Crystallography. She also laid the foundation for the ‘direct method', a new mathematical theory. In 1950 she was the first woman to become a member of the Royal Netherlands Academy of Arts and Sciences. She also held positions on the boards of various organisations outside of academia.

A detail worth mentioning is that she gave the initial impetus to graphic artist M.C. Escher's international breakthrough. MacGillavry was intrigued by the symmetry in the Dutchman Escher's work, which shows some similarities with her own work. In 1960, this prompted her to invite him to exhibit his work at the International Union of Crystallography's conference in Cambridge. She also published a book on Escher's drawings.

You can find MacGillavry in Amsterdam to this day, as the main access road to the Science Park Amsterdam, home to the Faculty of Science, was named after Carolina MacGillavry.