In Vibrio cholerae, the master regulator FlrA controls transcription of downstream flagellar genes in a σ54‐dependent manner. However, the molecular basis of regulation by VcFlrA, which contains a phosphorylation‐deficient N‐terminal FleQ domain, has remained elusive. Our studies on VcFlrA, four of its constructs, and a mutant showed that the AAA+ domain of VcFlrA, with or without the linker ‘L’, remains in ATPase‐deficient monomeric states. By contrast, the FleQ domain plays a pivotal role in promoting higher‐order functional oligomers, providing the required conformation to ‘L’ for ATP/cyclic di‐GMP (c‐di‐GMP) binding. The crystal structure of VcFlrA‐FleQ at 2.0 Å suggests that distinct structural features of VcFlrA‐FleQ presumably assist in inter‐domain packing. VcFlrA at a high concentration forms ATPase‐efficient oligomers when the intracellular c‐di‐GMP level is low. Conversely, excess c‐di‐GMP locks VcFlrA in a non‐functional lower oligomeric state, causing repression of flagellar biosynthesis.