ABSTRACT This research examines the role of organisational culture (OC) and supply chain integration (SCI) in improving sustainable supply chain performance (SSCP) in the food manufacturing industry in the UK. A competing value framework (CVF) was used to categorise OC into developmental, group, rational and hierarchical cultures. Qualitative interviews with 11 senior managers in the UK food industry were conducted and manually analysed. We found that three competing values in developmental, group and hierarchical cultures are effective in implementing and achieving higher SSCP. The values inherent in these cultures also trigger internal and external integration through which the firms acquire sustainability ideas, knowledge, training and skills from customers and suppliers to improve SSCP. We also found that within the context of sustainability, internal integration is critical to a successful external integration. The study contributes immensely to sustainability literature by highlighting the actual OC values relevant to achieving higher SSCP and establishing SCI’s mediating role. The study further assesses how SCI is established and formed by firms on the verge of achieving higher SSCP. Managers are advised to adopt blended competing values (developmental, group and hierarchical culture) and strengthen and heighten systemic SCI to implement sustainability practices, improve SSCP as well as overcome sustainability challenges.