The Firmicutes are an industrially and medically important group of gram-positive bacteria. They are used widely in industry in the biosynthesis of antibiotics and enzymes. They also encompass a number of clinically significant pathogenic strains, ranging from opportunistic pathogens to biowarfare agents, and are a major source of antibiotic-resistant infections. RNA polymerase is an essential enzyme responsible for DNA transcription encoded by all forms of cellular life. The essential role of RNA polymerase in transcription, coupled with its high degree of conservation between species makes it a prime target for the development of new antimicrobial compounds. Recently, advances in cryo-electron microscopy have facilitated the structural determination of this essential enzyme in several bacterial and eukaryotic species, providing structural and mechanistic information to facilitate efforts in drug development. The RNA polymerase of the Firmicutes differs significantly from previously determined structures, being the smallest multi-subunit RNA polymerase known. In addition, Firmicutes encode a number of transcription factors which facilitate RNA polymerase activity and are not found in other organisms. However, despite its far-reaching potential as an antimicrobial target, there is still no high-resolution structure of a Firmicute RNA polymerase available. In this study, RNA polymerase in complex with a novel transcription factor from a model Firmicute is examined via cryo-EM to provide structural and mechanistic insights into Firmicute transcription, and thereby, to facilitate the development of new antimicrobial strategies against this important group of pathogens.