physician and psychoanalyst sometimes referred to as the father of psychosomatic medicine because of his leading role in identifying emotional tension as a significant cause of physical illness.

Already a physician when he enrolled as the first student at the Berlin Psychoanalytic Institute (1919), Alexander became an assistant there and delivered a lecture series (1924–25) that grew into his first book, Psychoanalyse der Gesamtpersönlichkeit (1927; The Psychoanalysis of the Total Personality, 1930), a work developing the psychoanalytic theory of the superego and praised by Sigmund Freud (Freud, Sigmund). His success in applying psychoanalytic principles to the study and diagnosis of criminal personalities brought him an invitation to the United States (1930), where a professorship in psychoanalysis, the first post of its kind, was created for him at the University of Chicago. A year later, however, he went to Boston to collaborate with William Healy on a psychoanalytic study of delinquency, resulting in their book Roots of Crime (1935).

Alexander returned to Chicago in 1932 to establish the Chicago Institute for Psychoanalysis, which he directed until 1956. Under his leadership, the institute attracted many analysts and students who conducted extensive research on emotional disturbance and psychosomatic disease, identifying various disorders with particular unconscious conflicts. This work is represented in his book Psychosomatic Medicine: Its Principles and Applications (1950).

From 1938 to 1956, Alexander also served on the faculty of the department of psychiatry at the University of Illinois Medical School, Chicago. In 1956 he embarked on a new research program in psychotherapy and psychosomatic medicine at Mount Sinai Hospital, Los Angeles. His work there, conducted in cooperation with the University of Southern California and the Southern California Psychoanalytic Institute, explored the effect of the therapist's personality in the treatment process.

A notable authority on Freud, Alexander considered it essential to elaborate Freud's views. Yet he retained a certain independence from Freud (Freud, Sigmund), viewing disturbed human relations, rather than disturbed sexuality, as the main cause of neurotic disorders. One of his important works on Freud is Fundamentals of Psychoanalysis (1948). His The Western Mind in Transition: An Eyewitness Story (1960) is partly an autobiographical work, in combination with an analysis of modern civilization.