This paper explores the relationships between lean manufacturing (LM), the promotion of green practices, employee involvement, pressure to take actions against environmental issues, the adoption of an ISO 14001-based environmental management system (EMS) and environmental performance in order to understand how LM can help improve environmental performance through environmental practices and the development of a lean culture. The effects of pressure to “go green”, employee involvement and the adoption of an EMS based on the International Organization for Standardization’s standard ISO 14001 are discussed. Data were collected from 220 Chinese manufacturing firms and analyzed using partial least squares (PLS) regression. The results suggest that the implementation of LM has a positive effect on the promotion of green practices and consequent achievement of high environmental performance; employee involvement is a moderator that affects the relationship between green practices and environmental performance; pressure to “go green” is a mediator in the relationship between LM and green practices; however, the adoption of ISO 14001 does not act as a moderator on the relationship between LM and green practices, but synergies emerge if ISO 14001 is integrated with LM. The study shows the importance of human attitudes and fosters managers to develop the necessary mechanisms to ensure and enhance employee involvement and lean culture. Although these determinants of environmental sustainability have been studied separately until now, this paper analyzes them simultaneously, investigating the relationship between different strategies and shedding some light on successful actions that promote sustainable manufacturing, and on the role of LM in sustainability. The findings can help manufacturers to take the initiative to improve environmental performance and assist governments in implementing industrial policies.