At a time when American psychology was dominated by behaviorism, he developed the concept of self-help as a method in psychotherapy of the self in the 1920s.
His concepts influenced Maxwell Maltz in his writing of the classic self-help book, Psycho-Cybernetics.
George Kelly, in his book The Psychology of Personal Constructs, also credits Lecky as an influence.
Lecky stressed the defense mechanism of resistance as an individual's method of regulating his self-concept.
[4] He was well known as a psychologist and counseled John F. Kennedy when he was having trouble at Choate preparatory school.