Salicornia europaea L. (SE) as a halophyte has been widely used as a seasoned vegetable with various biological activities, including anti-inflammatory and anti-diabetic activities. In particular, the desalted SE (DSE) has been considered an attractive alternative compared to SE for its anti-obesity effect. 1-Deoxynojirimycin (1-DNJ) is one of the known α-glucosidase inhibitors and has been reported to have similar biological activities with SE. This study reports the anti-obesity and anti-inflammatory activities of DSE fermented by Bacillus velezensis K26 (BVDSE) previously isolated from Korean fermented soybean paste and elucidated to produce 1-DNJ in 3T3-L1 adipocytes and RAW264.7 cells. BVDSE (5%) did not show cytotoxicity in 3T3-L1 cells and inhibited lipid accumulation, which was decreased to 23% in the differentiated cells. BVDSE did not inhibit the release of the pro-inflammatory cytokine, TNF-α, while it remarkedly inhibited IL-6 on lipopolysaccharide-induced RAW264.7 cells. Taken together, these results indicate that the fermentation of DSE with B. velezensis K26 as a 1-DNJ producer has more significant anti-obesity and anti-inflammatory effects than even non-fermented DSE, assuming the synergistic effects by 1-DNJ production from B. velezensis K26, by which it could be highlighted that BVDSE may be considered for use as a functional food supplement.