A novel, Gram-reaction-positive, aerobic, rod-shaped, non-motile bacterial strain, designated NAL101(T), was isolated from gajami-sikhae, a traditional Korean fermented seafood made of flatfish. Growth occurred at 4-45 °C, at pH 5-10 and in 0-12 % (w/v) NaCl. Optimum growth occurred at 30-37 °C, at pH 8 and in 0-1 % (w/v) NaCl. The cell-wall amino acids were 2,4-diaminobutyric acid, alanine, glycine, threonine and glutamic acid and the major fatty acids were anteiso-C(15 : 0), iso-C(16 : 0) and anteiso-C(17 : 0). The predominant menaquinone was MK-11. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and an unknown glycolipid. The 16S rRNA gene sequence of strain NAL101(T) showed 97.7 % similarity to that of Leucobacter chironomi MM2LB(T), its closest relative. The DNA G+C content was 68.8 mol% and DNA-DNA hybridization values with closely related strains were <22 %. Phylogenetic analyses based on 16S rRNA gene sequences as well as differences in its physiological and biochemical characteristics indicated that strain NAL101(T) represents a novel species of the genus Leucobacter in the family Microbacteriaceae, for which the name Leucobacter celer sp. nov. is proposed. The type strain is NAL101(T) ( = KACC 14220(T) = JCM 16465(T)).