(1) Background: The increasing level of concern over reduction non-renewable resources, global warming, pollution, and social issues has led firms to initiate green and social activities. Furthermore, there is limited empirical evidence on the potential impact of green initiatives, corporate social responsibility (CSR), and reflective moral attentiveness (RMA) on sustainable performance. The purpose of this study was to investigate the mediating effect of reflective moral attentiveness (RMA) on the relationship between green supply-chain-management practices (GSCM) and CSR on sustainable performance. Based on the natural-resource-based view, stakeholder resource-based view, and signaling theory, this study investigated the role of GSCM practices and CSR in sustainable performance using cross-sectional data from the manufacturing and services industries from Khyber Pakhtunkhwa province, in Pakistan. (2) Methods: Using a non-probability convenience-sampling method, 500 employees were selected from the firms which are listed on the Pakistan stock exchange (PSE) and questionnaires were distributed. Complete questionnaires were received from 380 employees and used in the analysis, yielding a response rate of 76%. Partial least squares structural equation modeling (PLS-SEM) software was used for the confirmatory-factor analysis (CFA) and the testing of the hypotheses. The CFA results revealed the reliability and validity of the questionnaires. (3) Results: The results of the structural model (hypotheses testing) show that four attributes of GSCM practices (internal environmental management, green purchasing, cooperation with customers, and eco-design) have a positive influence on sustainable performance, while investment recovery and CSR were found to be insignificant. Moreover, there were significant and positive influences of GSCM and RMA on sustainable performance. On the other hand, control variables, such as gender, experience, and age, were found to have no significant role in sustainable performance. A further analysis revealed that reflective moral attentiveness mediated the relationship between GSCM, CSR, and sustainable performance. (4) Conclusions/implications: This study has several implications for green services and manufacturing firms specifically and for practitioners, researchers and academics in general. The innovation and novelty of this study lie in its determination of the contribution of RMA, GSCM, and CSR to achieving sustainable performance. Firms can improve their clean production activities by incorporating this model as a strategy. Future studies may add moderators and mediators to explore the impact of CSR and GSCM practices upon sustainability.