He then moved to the United States and completed training in endocrinology at The University of Chicago, and psychiatry at Albert Einstein in the Bronx as well as at Weill Cornell Medical College.

[16] Licinio was an assistant professor of psychiatry at Yale University, then he was a Unit Chief within the Clinical Neurodocrinology Branch of the National Institute of Mental Health at the NIH Intramural Research Program (1993–1999), and later was professor of psychiatry and medicine/endocrinology at the David Geffen School of Medicine at UCLA from 1999 until 2006, where he had multiple roles, such as Founding Director of three NIH funded programs: the Interdepartmental Center on Clinical Pharmacology.

[2] In 2006, he was appointed the Miller Professor of Psychiatry, Chairman of Psychiatry and Behavioral Sciences and subsequently associate dean for project development, responsible for starting the Clinical and Translational Science Institute at the University of Miami Miller School of Medicine, where he worked until 2009,[17] when he moved to Australia as Director of the John Curtin School of Medical Research.

Licinio returned to the US in 2017 as Senior Vice President for Academic and Health Affairs, Executive Dean, College of Medicine, and in 2019 he was appointed SUNY Distinguished Professor in the Departments of Psychiatry, Pharmacology, Medicine and Neuroscience & Physiology at State University of New York Upstate Medical University in Syracuse, New York.

[21] The key issue addressed during his term was the Genetic Information Nondiscrimination Act (GINA), which was strongly supported by the SACGHS.

[24] He has published collaboratively with 190 colleagues from 54 institutions, located in 19 countries, including Nobel Laureates Andrew Schally[25] and Rita Levi-Montalcini.

[37] He then administered daily leptin injections to each of them, and found that after ten months, the patients had lost half of his or her original body weight.

[50][51][52][53][54] Wong and Licinio contributed some of the earliest work on the role of cytokines and immune mediators in the brain, with implications for the underlying biology of major depressive disorder,[55] and published scientific articles on the localisation of gene expression for interleukin 1 receptor antagonist,[56] interleukin 1 receptor, type I (IL1R1), also known as CD121a (Cluster of Differentiation 121a),[57] and inducible nitric oxide synthase (iNOS)[58] in mammalian brain.

[60] In collaboration with colleagues at Columbia University Licinio and his team showed that inflammation-mediated up-regulation of secretory sphingomyelin phosphodiesterase in vivo represents a possible link between inflammatory cytokines and atherogenesis.

[62] In a more recent and ongoing line of research, Licinio and collaborators are examining the effects of the human microbiota and the microbiome–gut–brain (MGB) axis in obesity with diabetes and on behaviors relevant to depression and schizophrenia, an emerging area which opens potentially novel avenues for the treatment of psychiatric disorders.