He worked in the Department of Psychiatry, Research Hospital and Bezmi Alem Vakıf University as an expert psychiatrist. Specially interested in the concepts of temperament and personality. Enver Demirel Yılmaz, found the Nine-Type Temperament Model as a new scientific model. He wrote many academic papers in order to develop The Nine Types of Temperament Model in the fields of psychology, psychotherapy, psychiatry and education, and all articles were published in international scientific journals. Also, Enver Demirel Yılmaz is the author of a total of four boks: 1- “Character and Personality Development in Children According to The Nine Types of Temperament Model”, 2- “Love of Temperament”, 3- “I am The Guide”, and 4- “I am The Parent”. He structured all his professional activities such as depression, bipolar disorder, obsessive compulsive disorder (obsession), anxiety, panic attacks, anger problems, personality disorders (dependent, timid, borderline, narcissistic etc.), sexual problems (vaginismus, erection problems, premature ejaculation, etc.) within the framework of Nine Types Temperament Model. In addition, with The Nine Types Temperament Model trainings, he contributed to the personal and professional development of many psychiatrists, psychologists and educators.