Here, a Bacillus strain, UTK D1-0055, is described that was isolated from a laboratory environment. It was of interest as it demonstrated antilisterial activity. The genome was sequenced, which identified the strain as Bacillus altitudinis, and a high-quality complete annotated genome was produced. Additionally, the taxonomy of this and related species was evaluated, including B. aerophilus, B. pumilus, B. safensis, B. stratosphericus, and B. xiamensis, which is unclear and contains errors in public databases such as NCBI. The included strains grouped into seven clusters based on average nucleotide identity (ANI). Strains designated as B. aerophilus, B. altitudinis, and B. stratosphericus grouped together in the cluster containing the B. altitudinis type strain, suggesting that they should be considered a single species, B. altitudinis. Furthermore, the antimicrobial activity of UTK D1-0055 was determined against a panel of 15 Listeria spp. strains (including nine L. monocytogenes serotypes, L. innocua, and L. marthii), other foodborne pathogens (six Salmonella enterica serotypes and Escherichia coli), and three representative fungi (Saccharomyces cerevisiae, Botrytis cinerea, and Hyperdermium pulvinatum). Antibacterial activity was observed against all Listeria spp. strains, but no antagonistic effects were observed against the other bacterial or fungal strains tested. Biosynthetic gene clusters were identified in silico that may be related to the observed antibacterial activity, which included clusters that putatively encode bacteriocins and nonribosomally synthesized peptides. The Bacillus altitudinis strain identified in the present investigation showed a broad range of antilisterial activity, suggesting that it and other related strains may potentially be evaluated for their biocontrol potential in the food industry.