The purpose of this research was to find out how workplace flexibility affects the employees’ flexibility in order to increase their career satisfaction while reducing their workplace stress with the mediating role of goal orientation. Employees need workplace flexibility to develop a better sustainable career. In doing so, the relationship between workplace flexibility and career satisfaction can be affected by two different factors. One of them is job stress, which can be a mediating factor, and the second is goal orientation, which in this study was considered as a moderator between two variables. For this research, a quantitative research method was applied, and a survey was distributed to 216 respondents, namely, everyone working in handling in a single aviation sector of North Cyprus, to obtain better and clearer results from the respondents. A pilot test was completed and data were collected face-to-face in order to observe the reaction of respondents to develop better results and reduce any mistakes that could arise by answering the questionnaire. Moreover, in order to test the reliability of questionnaires, a pilot test was completed with 14% of the respondents and the results were evaluated by examining Cronbach’s alpha. Job stress is a negative term; therefore, surprisingly, there was a positive correlation between workplace flexibility and job stress in the findings. The results were discussed and specifically analyzed with the literature review. Findings of the article clarify that workplace flexibility, along with goal orientation, is expected to positively contribute to the sustainable career satisfaction of employees in the handling sector. This research will make an important contribution to the existing literature pertaining to flexible arrangements in the workplace, sustainable career satisfaction, job stress, and goal orientation, and will contribute to further theories in this field.