The primary objective of this research is to explicate the dynamic model of career mobility within the inter-generational paradigm and to select the most optimal managerial strategy for retaining human capital by analyzing the lived experiences of managers at the National Bank of Iran (Bank Melli Iran). This study was conducted using a mixed-methods (qualitative-quantitative) approach and an exploratory-sequential strategy. In the first phase, using descriptive phenomenology and Colaizzi’s method, the lived experiences of 15 expert managers who interacted with generations X, Y, and Z were analyzed. In the second phase, the identified components were modeled using the Fuzzy Cognitive Map (FCM) approach, and the system dynamics were simulated under various scenarios. Qualitative findings revealed that the meaning of mobility has transformed from an "inevitable deviation from stability" in Generation X, to "searching for meaning" in Generation Y, and a "strategy for advancement and rapid adaptation" in Generation Z. The results of the quantitative analysis of Fuzzy Cognitive Maps and centrality indices showed that the combination of "Gen Z fluidity" with "organizational structural challenges" is the main driver of the turnover rate. Furthermore, sensitivity analysis demonstrated that "Human Resource Strategies," with 13.5%, possess the highest leverage power in controlling mobility, whereas "changing management style" alone plays a limited role (3.1%). Simulation results indicate that successful management of generational succession requires a transition from the traditional "career ladder" model to the "career network" model. Based on the 80-20 rule, it is suggested that organizations focus their primary attention on structural reforms (flexible paths and personalized rewards) and their complementary focus on cultural measures (reverse mentoring).