The purpose of this study is to examine the process of the change of consciousness and behavior through the experiences of full-time union officers. The survey targeted 16 officers (average age: 46.3 years). Semi-structured interviews were conducted. A verbal protocol was developed for the interview contents, which were then analyzed by the modified grounded theory approach (M-GTA). It was determined that theoretical saturation was reached with 40 concepts, 15 sub-categories and 6 categories. In the change process of the consciousness and behavior, the full-time officers experienced “situations and state of mind before taking the post” and proceeded to “carry out their role as a full-time officer,” which was influenced by the “change of consciousness as a full-time officer,” “relationship with union members,” and “relationships inside and outside the company,” leading to a “connection with the current situation.”