Shared electric scooter services (SESS) have gained popularity in many cities as an emerging mobility mode. However, SESS is attributed to low utilization rates in some cities. In this context, the significance of users’ satisfaction with the provided services, along with their loyalty, becomes particularly pronounced. Therefore, it is essential to evaluate the service quality (SQ) from the users’ perspective and understand its effect on satisfaction and loyalty, which are critical factors for the long-term durability and success of service. Thus, this study examines the determinants of user satisfaction and loyalty toward SESS. For this, we conducted an online survey among the SESS users in Chicago. We analyzed the responses using partial least squares structural equation modeling (PLS-SEM) and reflexive thematic analysis (TA). Our results confirm the quality-value-satisfaction-loyalty paradigm and indicate that users’ perceptions of SQ, including safety and security, service availability, interface, and perceived affordability, significantly contribute to user loyalty enhancement toward SESS. Perceived value (hedonic value, utilitarian value, and perceived affordability) and satisfaction mediate the impact of SQ on loyalty. Additionally, the results indicate that those who perceive SESS as cost-effective report higher satisfaction levels. Furthermore, users who have pro-environmental attitudes and view SESS as environmentally friendly are more likely to derive hedonic value from the service and exhibit higher loyalty. The TA uncovers key challenges from the user perspective, including pricing, service timing, end-trip facilities (e.g., parking), street pavement condition, vendor operational zoning, and fleet quality, with a specific emphasis on GPS accuracy. These findings provide valuable insights into user behavioral mechanisms, which can be considered as a manifest for service improvement and enhancing efficiency.