Lean practices are shown to enable the optimization of production processes. However, the true meaning of Lean extends beyond the mere application of practices, emphasizing people’s involvement and respect and acting as a robust learning approach rooted in Gemba. It enhances creativity and autonomy in problem-solving. Nevertheless, the importance of the human-centred aspect of Lean in the era of Industry 5.0 often remains theoretical as many managers and practitioners focus solely on Lean practices to achieve immediate results, neglecting the role of operators’ learning. This paper presents a methodology that integrates continuous learning into production optimization through use of a Plan-Do-Check-Act improvement cycle, placing employee learning at its core. The case company ElecTech specializes in the manufacturing of electric pylons, involving multiple fabrication and assembly operations. The paper examines various production setup-time configurations and Single-Minute Exchange of Die applications at ElecTech, where operators’ roles and interventions differ across scenarios. The results underscore the critical role of employee engagement in enhancing Lean outcomes, demonstrating the significant impact of operators’ learning on reducing lead times during production changeovers in which workers were involved. This paper reinforces the concept that Lean is not just about optimization; it is more fundamentally about continuous improvement – through the continuous development of people.