She was a National Institute of Standards and Technology (NIST) Fellow and Scientist Emeritus in the Sensor Science Division.

She received a Ph.D. degree in physical chemistry from Cornell University in September 1956, under the guidance of Prof. Simon H. Bauer.

Jacox spent the next two years as postdoctoral research fellow in the chemistry department of the University of North Carolina in Chapel Hill, working with Prof. Oscar K.

[13] Marilyn E. Jacox passionately researched and published the genealogy of her ancestors throughout her life,[14][15] as well as being an ardent world traveller and photographer along the way.

[3] Friends and family were regularly treated to slide and video shows that could compete with the best documentaries.

Owing to the discrimination she experienced during her career, Jacox left $1.5 million to Cornell University's college of arts and sciences to provide scholarships for female undergraduate students majoring in science and math fields.