We elucidate the life cycle of Leuceruthrus stephanocauda (Faust, 1921) Womble and Bullard 2022, provide the first description of its adult, and redescribe its cercaria based on specimens infecting centrarchiform and perciform fishes and pleurocerid snails in the southeastern United States. Based on morphological and nucleotide-based (28S rRNA gene and internal transcribed spacer 2 [ITS2]) evidence, adults of L. stephanocauda infect the stomach of spotted bass, Micropterus punctulatus (Rafinesque, 1819), green sunfish, Lepomis cyanellus Rafinesque, 1819, and longear sunfish, Lepomis megalotis (Rafinesque, 1820) from Chewacla Creek (Tallapoosa River, Alabama) and mottled sculpin, Cottus bairdii Girard, 1850 (juvenile), from Raccoon Creek (Chattooga River, Georgia). The adult of L. stephanocauda differs from its congeners by having an elongated body and an asymmetrical vitellarium. The cercariae of L. stephanocauda shed from yellow elimia, Elimia flava (Lea, 1862) (Cerithioidea: Pleuroceridae) in Chewacla Creek and Moores Mill Creek (Tallapoosa River) and from Elimia caelatura georgiana (Lea, 1862) in Raccoon Creek. Naturally shed cercariae of L. stephanocauda are unique by having bilateral, discontinuous fields of black tail stem pigmentation posterior to the withdrawn distome and along the margins of the paired furcae, prominent subtriangular spines on the anterior end of the tail stem anterior and posterior to the distome, and broadly rounded to lanceolate furcae that are longer than wide and that bear numerous marginal and submarginal protuberances. Our 28S phylogenetic analysis recovered L. stephanocauda as a sister to Leuceruthrus micropteri Marshall and Gilbert, 1905, within monophyletic Leuceruthrinae Goldberger, 1911. No species of Leuceruthrus Marshall and Gilbert, 1905, has been reported previously from the Tallapoosa River.