Erickson is noted for his often unconventional approach to psychotherapy, as described in the book Uncommon Therapy by Jay Haley and the book Hypnotherapy: An Exploratory Casebook, by Milton H. Erickson and Ernest L. Rossi (1979, New York: Irvington Publishers, Inc.). He developed an extensive use of therapeutic metaphor and story as well as hypnosis and coined the term brief therapy for his method of addressing therapeutic change in relatively few sessions.

Beginning in the 1950s, Erickson's use of interventions influenced strategic therapy and family systems therapy practitioners including Virginia Satir and Jay Haley. He was noted for his ability to "utilize" anything about a patient to help them change, including their beliefs, favorite words, cultural background, personal history, or even their neurotic habits.

Through conceptualizing the unconscious as highly separate from the conscious mind, with its own awareness, interests, responses, and learnings, he taught that the unconscious mind was creative, solution-generating, and often positive.

He was an important influence on neuro-linguistic programming (NLP), which was in part based upon his working methods