Kingella kingae is a gram-negative coccobacillus that colonizes the oropharynx of young children and is recognized as the most common cause of osteoarticular infections in children between the ages of six months and four years of age. Critical K. kingae virulence determinants include a polysaccharide capsule and a galactofuranose exopolysaccharide, called galactan. The galactan is encoded by the pamABC genes in the pamABCDE locus. Using homology-based approaches, we identified the pamD and pamE genes as putative lipopolysaccharide (LPS) glycosyltransferases, prompting us to conduct an exploration of the K. kingae LPS. We determined that the K. kingae LPS contains an atypical O-antigen and a high molecular weight (HMW) LPS species dependent on expression of the pamABC genes. Using immunochemical assays in combination with mass spectrometry and NMR, we determined that the HMW LPS contains galactan. Furthermore, deletion of the pamDE genes resulted in loss of both the O-antigen and the HMW LPS. Taken together these data demonstrated that the galactan is a modification of the O-antigen, representing a novel mechanism of exopolysaccharide surface anchoring. We identified an LPS heptosyltransferase II gene, rfaF. Deletion of this gene resulted in a truncated LPS, lacking the O-antigen, the HMW LPS and residues of the core oligosaccharide. The ΔrfaF mutants displayed increased levels of resistance to normal human serum and polymyxin B, suggesting that the LPS contributes to membrane homeostasis. Future studies will characterize changes in membrane properties in ΔrfaF mutants. To identify capsule/galactan independent serum resistance factors, we used a high-throughput Tn-seq assay. Putative serum resistance factors include oxidoreductase and pyrimidine biosynthesis genes. Future validation studies will confirm the role of these genes in K. kingae serum resistance. Ultimately this work establishes that the K. kingae galactan is anchored to the bacterial surface through a novel mechanism requiring the LPS O-antigen. This work also demonstrates that the K. kingae LPS is a crucial regulator of membrane homeostasis, highlighting the role of the LPS in various immune evasion processes.