The genomics era has substantially revolutionised the way we study the variety of glycan and polysaccharide structures produced by bacteria that decorate their cell surface. The ability to correlate information from genome sequences with chemical structures of polysaccharides produced by individual strains offers a powerful approach linking the disparate fields of genomics and carbohydrate chemistry. Over the last decade, my team has refined this ‘genomics-structure’ approach using the Gram-negative pathogen, Acinetobacter baumannii. This has opened doors to the discovery of new sugars, novel structures, biosynthesis pathways, and evolutionary mechanisms. We discovered that A. baumannii produces capsular polysaccharide (CPS), overturning decades of historical literature reporting the structure as lipopolysaccharide (LPS) with O-antigen as is the case for most Gram-negative bacteria. We also defined the chromosomal ‘K locus’ (KL) responsible for CPS biosynthesis, developed a nomenclature system and curated database for KL typing, and fully characterised the suite of genes required for the biosynthesis of more than 200 CPS structures without the need for biochemistry. This approach has also led to the more recent discovery of genes outside the K locus that are imported by bacteriophage to alter the CPS structure. As structural changes can affect the specificity of antibodies and phage currently being investigated as alternate therapies to antibiotics, the ‘genomics-structure’ approach has proven to be a valuable workflow for robust CPS characterisation, informing improvements to bacterial typing and surveillance of important pathogens.