[2] Neidhardt's independent research career began when he joined the Purdue faculty in 1961.
[2] During that time he served in a number of other administrative roles, including associate dean for faculty in the medical school and Vice President for Research.
[2] Neidhardt authored or coauthored several widely recognized textbooks and reference works, including an important treatise on bacterial growth titled Escherichia coli and Salmonella: Cellular and Molecular Biology.
[2] He spent almost twenty years on the board of the Waksman Foundation for Microbiology housed at Swarthmore College and served as its president.
[2][6] Neidhardt was a Quaker and was noted by friends for his dedication to social causes, including support for women and minority scientists.