tRNA-modifying enzymes are emerging as key regulators of bacterial physiology. MiaA, a tRNA isopentenyltransferase, is well studied in model organisms, but its role in the pathogen Pseudomonas aeruginosa remains unclear. Using LC–MS, nanopore sequencing, and transcriptional, translational and proteomic profiling, we mapped MiaA-dependent tRNA modifications and revealed unexpected effects of MiaA loss. Impaired translation of MiaA-sensitive codons reduced quorum-sensing–controlled virulence gene expression and attenuated pathogenicity in Galleria mellonella. Ribosome stalling at trp codons in miaA mutants caused overproduction of tryptophan- normally restrained by attenuation- along with upregulation of cognate tRNAs, linking translation to global metabolic adaptation. MiaA is tightly regulated and so central to bacterial physiology that its expression level correlates directly to virulence in clinical isolates, highlighting its role as a hub connecting translation, transcription, metabolism, and pathogenicity. These findings position MiaA as a key integrator of cellular processes critical for pathogen fitness and host interactions.