jats:sec<jats:title content-type="abstract-subheading">Purpose</jats:title>jats:pThe purpose of this paper is to investigate the interplay between configuration dimensions (network structure, network flow, relationship governance, and service architecture) of last-mile supply networks (LMSN) and the underlying mechanisms influencing omnichannel performance.</jats:p></jats:sec>jats:sec<jats:title content-type="abstract-subheading">Design/methodology/approach</jats:title>jats:pBased on mixed-method design incorporating a multiple embedded case study, mapping, survey, and archival records, this research involved undertaking in-depth within- and cross-case analyses to examine seven LMSNs, employing a configuration approach.</jats:p></jats:sec>jats:sec<jats:title content-type="abstract-subheading">Findings</jats:title>jats:pThe existing literature in the operations management (OM) field was shown to provide limited understanding of LMSNs within the emerging omnichannel context. Case results suggest that particular configurations have intrinsic capabilities, and that these directly influence omnichannel performance. The study further proposes a taxonomy of LMSNs comprising six forms, with two hybrids, supporting the notion of equifinality in configuration theory. Propositions are developed to further explore interdependencies between configurational attributes, refining the relationship between LMSN types, and factors influencing omnichannel performance.</jats:p></jats:sec>jats:sec<jats:title content-type="abstract-subheading">Practical implications</jats:title>jats:pThe findings provide retailers with a set of design parameters for the (re)configuration of LMSNs and facilitate performance evaluation using the concept of fit between configurational attributes. The developed model sheds light on the consequential effects when certain configurational attributes are altered, preempting managerial attention. Given the global trend in urbanization, improved LMSN performance would have positive societal impacts in terms of service and resource efficiency.</jats:p></jats:sec>jats:sec<jats:title content-type="abstract-subheading">Originality/value</jats:title>jats:pThis is one of the first studies in the OM field to critically analyze LMSNs and their behaviors in omnichannel retailing. Additionally, the paper offers several important avenues for future research.</jats:p></jats:sec>