Abstract We propose a strategy to achieve low wear in a complex concentrated alloy (CCA) CrFeNiNb with multi-phase hierarchical microstructure. The CCA consists of a matrix of ultrafine-grained hexagonal close-packed (HCP) Laves phase (80.3 vol%), a secondary face-centered cubic (FCC) phase (18.3 vol%), a minor amount of (Nb,Cr)-oxides and a trace amount of uniformly dispersed nanoscale precipitates. The CrFeNiNb CCA shows an ultrahigh hardness of 993 (±22) HV and extremely low wear rate of 7.4 (±0.6) × 10−6 mm3/(N·m) upon sliding against silicon nitride (Si3N4) ball. To explore the wear mechanism, we characterized the morphology, chemical composition and cross-sectional microstructure of the wear track. The results show that the cracked oxide layer, subgrain formation in the FCC phase, and the Shockley partial and full dislocations-triggered intragranular prismatic slip in the C14 Laves phase synergically contribute to the exceptional wear resistance. Furthermore, the chemical composition and crystal structure of the cracked oxide layer were analyzed in detail and the subsurface deformation of HCP/FCC phases was comprehensively discussed. These findings provide significant insight into the design of wear-resistant alloy via the formation of multi-phase hierarchical microstructure. We propose a strategy to achieve low wear in a complex concentrated alloy (CCA) CrFeNiNb with multi-phase hierarchical microstructure. The CCA consists of a matrix of ultrafine-grained hexagonal close-packed (HCP) Laves phase (80.3 vol%), a secondary face-centered cubic (FCC) phase (18.3 vol%), a minor amount of (Nb,Cr)-oxides and a trace amount of uniformly dispersed nanoscale precipitates. The CrFeNiNb CCA shows an ultrahigh hardness of 993 (±22) HV and extremely low wear rate of 7.4 (±0.6) × 10−6 mm3/(N·m) upon sliding against silicon nitride (Si3N4) ball. To explore the wear mechanism, we characterized the morphology, chemical composition and cross-sectional microstructure of the wear track. The results show that the cracked oxide layer, subgrain formation in the FCC phase, and the Shockley partial and full dislocations-triggered intragranular prismatic slip in the C14 Laves phase synergically contribute to the exceptional wear resistance. Furthermore, the chemical composition and crystal structure of the cracked oxide layer were analyzed in detail and the subsurface deformation of HCP/FCC phases was comprehensively discussed. These findings provide significant insight into the design of wear-resistant alloy via the formation of multi-phase hierarchical microstructure.