"The objective of this article is to analyze the implementation of the Lean Manufacturing (LM) strategy in a multinational auto parts company located in León, Guanajuato through the reconstruction of its trajectory during the period 1997 to 2018. To do that, a qualitative research was carried out, longitudinal, through a case study. Field work research was performed in three moments: from August to September of 2012, from June to July of 2015, and April 2018; in-depth interviews were applied with blue-collar workers, front-line managers, mid-level managers as well as top-level managers. Three stages were identified: a) Nascent Lean Manufacturing: The Beginnings, b) Foundations of the Alpha Production System, and c) Towards and inclusive Alpha Production System. With special emphasis on the analysis of the third stage, the main findings were the important role played by soft lean tools: observation and workers’ involvement; as well as institutional factors: sector of belonging, size of the company, ownership of capital and relationship with its main client."