Using a change management perspective, this paper studies the implementation process of life cycle thinking and sustainable design in practice, based on empirical data from eight firms involved in product development. The data indicate that different firms take different trajectories and approaches towards implementation, which in turn depends on a number of human factors, including participation of employees, training, resistance to change etc. As a result of this study, a model for the implementation of sustainable design is presented. Firms can use the model and the insights for the improvement and adaptation of existing methodologies and for choosing a fitting approach for integrating life cycle thinking.