[1] In this time he also co-authored his first article on Renaissance Dutch anatomist Andreas Vesalius, "Vesalius as a clinician" (Bulletin of the History of Medicine, December 1943), and thus began a long series of collaborations with University of California, Berkeley professor of anatomy and medical history John Bertrand deCusance Morant Saunders (1903–1991).
[5] He served as director of Stanford's Lane Medical Library's historical collection 1949–1959[7] and rose to the rank of full professor in 1951.
B. deC. M. Saunders continued their collaboration to publish extensively on Vesalius, Leonardo da Vinci, Gabriele Falloppio, Michael Servetus, and other Renaissance anatomists.
B. deC. M. Saunders, John F. Fulton, and British physician and historian of medicine Charles Singer; Fulton and Singer had themselves been interested in Vesalius by Canadian physician and medical history collector William Osler and were enabled by library collection work done by Harvey Cushing at Osler's earlier suggestion.
[1] O'Malley was promoted in 1966 to be the head of UCLA's newly created department of medical history, a position which he retained until his sudden death.
[5] During the 1950s and 1960s he corresponded extensively with leading medical historians such as John F. Fulton, F. N. L. Poynter, and Charles Singer.
In 1965 he received the History of Science Society's Pfizer Award and the Commonwealth Club of California's silver medal.
As a posthumous honor, UCLA established the Charles Donald O'Malley Short-Term Research Fellowships.