Employee Experience (EX) has become a strategic pillar in the management of the human capital work cycle. Therefore, this study seeks to examine how EX is configured during the organizational socialization process. A qualitative research study was designed, guided by Interpretive Phenomenological Analysis (IPA), based on the narratives of 184 Spanish-speaking professionals belonging to generations X, Millennials, and Z, who recounted their onboarding experiences. The findings highlight that the alignment between initial expectations and actual experiences, along with the social support provided by managers, peers, and mentors, play a fundamental role in positive emotional EX. Furthermore, generational differences were observed in the value attributed to the onboarding structure, technological resources, communication, and the quality of interpersonal interactions. Shorter career trajectories were associated with a greater reliance on social resources to build a positive onboarding experience. The results offer an interpretive framework that links expectations, available resources, and organizational climate as critical factors for integration and engagement in the early stages. From an applied perspective, the study proposes differentiated strategies for designing generationally adapted onboarding programs that improve the subjective experience, reinforce the sense of belonging, and contribute to talent retention. Specifically, eight distinct strategies are proposed that address generational differences and expectations. These include the design of multilevel gamified onboarding processes with shared leadership, information support (predictive through AI), and the promotion of high-impact mentoring practices to foster social support; the integration of micro sensory experiences and corporate rituals; generational personalization; and, among others, expectation labs, which could facilitate perceptual alignment, reinforcing transparency and psychological safety.