Early 1920s: As a student he was in contact with Paul A. Weiss who worked at the so called Prater Vivarium and came up with system ideas as a result from his experiments on butterflies.

1926: He earned his doctorate at the University of Vienna.

1934: The University of Vienna named him Privatdozent, a faculty lecturer with prestige but no pay.

1937-1938: He was awarded a Rockefeller Foundation fellowship to spend a year studying in biology in the United States, also working with the Russian physicist Nicolaus Rashevsky.

1938: During spring he took off for a cross-country (USA) lecture tour. From June to October, at the Marine Biological Laboratory in Woods Hole, he conducted flat-worm experiments in the nature of growth.

1939-1948: Extraordinary Professor at the Department of Zoology [University of Vienna]. He continued investigations into the nature of growth, including the abnormal growth of cancer. He taught biology to medical students.
Bertalanffy became a member of the NSDAP party (see Hofer, V. 1996. Organismus und Ordnung. Zur Genesis und Kritik der Systemtheorie Ludwig von Bertalanffy's. PhD thesis, University of Vienna).

1948-1949: Visiting Professor at the Medical School's Middlessex Hospital [University of London].

1949-1952: Professor of Biology at the McGill University in Canada. Professor of Biology and Director of Research at the Faculty of Medicine [University of Ottawa, Canada]. He began a series of experiments that culminated in the Bertalanffy Method of cancer cytodiagnosis. He developed mathematical equations that could be used to predict a given species' growth rate on the basis of that species' rate of metabolism. He went on an eighteen-university lecture tour in USA.

1954-1955: Founding Fellow at the Ford Foundation's Center for Advanced Studies in the Behavioral Sciences at Stanford, California.

1954-1958: Professor at the Center for Advanced Studies in the Behavioral Sciences in Stanford. Co-director in charge of biological research at Mt Sinai Hospital in Los Angeles. He conducted studies of hallucinogenic and tranquilizing drugs used in psychiatry. Visiting Professor at the department of Physiology, at the School of Medicine [University of Southern California in los Angeles]. He gave lectures at the Hacker Psychiatric Clinic in Beverly Hills.

1958-1961: Alfred P. Sloan Visiting Professor at the Menninger Foundation in Topeka, Kansas.

1961-1966: He founded the Center for Advanced Studies in Theoretical Psychology at the University of Alberta, Edmonton.

1966-1969: Professor of Theoretical Biology (later University Professor) and member of the Center for Advanced Study in Theoretical Psychology at the University of Alberta in Edmonton, Canada. He was co-teacher of a seminar on theoretical psychology and the philosophy of science. He gave a series of lectures in Germany, sponsored by the Reimers Foundation for Anthropogenic Research, about his method of cancer diagnosis.

1969- 1972: Faculty Professor at the Center for Theoretical Biology, State University of New York, Buffalo, appointed to the faculty of Social Sciences, but assigned to the Center for Theoretical Biology. He gave courses on systems science and philosophy: "Science, Society and Culture", "Perspective Philosophy and the New Image of Man".

He was:

• Honorary Fellow of the American Psychiatric Association
• Member of the Deutsche Akademie der Naturforscher,
• Fellow of the International Academy of Cytology,
• Fellow of the American Association for the Advancement of Science,
• Editor of General Systems Yearbook of the Society for General Systems Research.

As a researcher he was recognized for his discoveries in comparative physiology of metabolism and growth, and the explicit identification of laws governing the processes of growth and adaptation.

In 1972 R. Buckminster Fuller was asked by a committee of French scientists to write a paper on Ludwig von Bertalanffy's nomination for the Nobel Prize. He did so. The nomination went to Oslo, but the committee's effort came just to late. Ludwig died before the nomination of him could be considered by the Nobel authorities.

June 12, 1972: Bertalanffy died of a heart attack. He was buried in Montreal.