The Asian tiger mosquito, Aedes albopictus, is an invasive species and a vector for several significant human pathogens. Gaining a deeper understanding of its reproductive biology offers valuable insights into its evolutionary success and may inform the development of sustainable strategies to control its spread. This study presents a comprehensive structural and functional characterization of the fruitless gene in Ae. albopictus (Aalfru), a pivotal regulator of sexual behavior in insects. Through in silico analysis combined with molecular and functional genetics approaches, we identified a high degree of conservation in the fru gene structure and its regulation via sex-specific alternative splicing. Differently from Drosophila, Aedes aegypti, and other dipteran fruitless orthologs, Aalfru sex-specific regulation starts in 1-day-old embryos, rather than the late larval stage. Functional analysis using embryonic RNA interference (RNAi) demonstrated that, Ae. albopictus males with transiently disrupted fru expression at the embryonic stage showed significant deficits in adult mating behavior and failed to produce viable progeny. Our findings elucidate the Aalfru gene’s molecular organization, developmental regulation, and critical role in courtship behavior, highlighting its importance in male sexual behavior and reproductive success in Ae. albopictus.