<jats:title>Abstract</jats:title><jats:p><jats:italic>Aspergillus aculeatus</jats:italic>, a filamentous fungus belonging to the <jats:italic>Aspergillus</jats:italic> clade Nigri, is an industrial workhorse in enzyme production. Recently we reported a number of secondary metabolites from this fungus; however, its genetic potential for the production of secondary metabolites is vast. In this study we identified a 6‐methylsalicylic acid (6‐MSA) synthase from <jats:italic>A. aculeatus</jats:italic>, and verified its functionality by episomal expression in <jats:italic>A. aculeatus</jats:italic> and heterologous expression in <jats:italic>A. nidulans</jats:italic>. Feeding studies with fully <jats:sup>13</jats:sup>C‐labeled 6‐MSA revealed that 6‐MSA is incorporated into aculinic acid, which further incorporates into three compounds that we name aculins A and B, and epi‐aculin A, described here for the first time. Based on NMR data and bioinformatic studies we propose the structures of the compounds as well as a biosynthetic pathway leading to formation of aculins from 6‐MSA.