His research focused on the biochemical underpinnings of physiology and included characterizing acid-base homeostasis in blood and pioneering the use of radioactive tracers for studying metabolism.
Hastings received a number of honors and awards for his work, including election to the National Academy of Sciences in 1937 and the President's Medal for Merit in 1948 following his wartime service on the Committee for Medical Research.
After graduation, Hastings began his undergraduate work at the University of Michigan, originally intending to study chemical engineering but switching to chemistry after being recruited as a laboratory assistant by physical chemist Floyd Bartell.
In 1930, he served as a visiting professor at the Peking Union Medical College in China, where he worked with Otto Folin's former student Hsien Wu.
During his tenure, Hastings was recognized as an enthusiastic teacher of medical students and mentor to the scientists in his research group, noted later for producing an unusual number of future professors of clinical medicine.
[2] In connection with this role, Hastings traveled to Moscow to meet with Soviet scientists and share samples of penicillin, then being actively studied by CMR-funded projects.
Wanting to continue to focus on research rather than administration, he recruited Frank Huennekens to Scripps to build and develop the biochemistry department there, much as Hastings had previously done at Harvard.
[1] In 1966 Hastings became one of the first faculty members of the newly established University of California, San Diego School of Medicine, where he joined the neurosciences department and worked on curriculum development.