The development of antimicrobial resistance drives the search for molecules capable of inhibiting bacterial virulence. Fungi of the Basidiomycota phylum constitute an important source of compounds with antimicrobial activity. The present paper describes a new species named Fulvifomes mexicanus sp. nov. based on morphological and phylogenetic analyses. The methanolic extract of basidiome of this fungus inhibited the motility of Pseudomonas aeruginosa ATCC 9027 and the production of violacein by Chromobacterium violaceum CV026. The metabolomic study of the extract by liquid chromatography-high-resolution electrospray ionization mass spectrometry (LC-HRESIMS) and molecular networking analyses revealed the presence of a complex composition of metabolites including hispidin derivatives, terpenoids, phenols, furanones, alkylglycerols, pyrones, and γ-butyrolactones, among others. Overall, this work represents the first chemical and biological study of a new species of Fulvifomes mexicanus as a source of antipathogenic metabolites for the development of novel antimicrobial agents.