This study aims to investigate the role, characteristics, and procedures that refer to the development and self-assessment of modern adult educators, focusing on the case of School Counselors in the Prefecture of Thessaloniki. To achieve this aim, quantitative research was conducted with the use of a questionnaire that was completed by the 68 School Counselors who took part in the survey. The results of the research showed that the participating School Counselors argue that the role of the modern School Counselor is multifaceted as he is a Trainer, Organizer and Teacher. They also argue that the main characteristics that should govern the modern School Counselor are the ability to create a collaborative learning environment and to set cognitive goals. They also argue that regular self-assessment of school counselors and the need for self-criticism are necessary. The main development strategies that the modern School Counselor should use are Action Research, Reflection, and Teamwork. As an effect, providing further training to School Counselors on these issues is an imperative need, so that they be able to become more effective in their complex work environment. Finally, with regard to the originality of this research study, it should be noted that no other similar study has been conducted in Greece yet, which would combine the role, characteristics, and procedures that apply to the self-assessment and development procedures of School Counselors.