The Staphylinidae contain over 57,000 described species, thus comprising one of the largest families in all Insecta. Leehermania prorova Chatzimanolis, Grimaldi, and Engel, new genus and species, is described, which is the earliest staphylinid and the oldest definitive polyphagan beetle. The new species is based on a series of well-preserved specimens from the early Norian to late Carnian-aged (Late Triassic) Cow Branch Formation of southern Virginia. It is considered to be subfamily incertae sedis within Staphylinidae, but its possible affinity with the tachyporine group of staphylinids is noted. A summary of all Mesozoic Staphylinidae is provided and the evolutionary history of the lineage briefly discussed.