Since 1978 Greenberg has been affiliated with the William Alanson White Institute, currently as a faculty member, supervisor, and training analyst.
Through this Institute he has been influenced by its founders, Harry Stack Sullivan, Erich Fromm, Frieda Fromm-Reichmann and Clara Thompson.
[3] A complete issue of Contemporary Psychoanalysis[4] was devoted to the much-quoted[5][6][7][8][9] Object Relations in Psychoanalytic Theory in 2013, the 30th anniversary of its publication.
In his second book, Oedipus and Beyond,[10] Greenberg further develops his deep and careful interpretation of the history of psychoanalytic thinking, and its implications for clinical practice.
In more than 70 articles and book chapters, Greenberg has made a number of contributions to comparative psychoanalysis, to the history of psychoanalytic ideas,[11] and to moving forward the theory of therapeutic action [12][13][14] and of ways of understanding the nature of psychological conflict.