Developmental stress can have sustained effects on animal phenotype and performance across life-history stages. For example, developmental stress is known to decrease the quality of sexually selected traits (e.g. bird song), and therefore is thought to decrease reproductive success. However, animals exposed to developmental stress may compensate for poor quality sexually selected traits by pursuing alternative reproductive tactics. Here, we examine the effects of developmental stress on adult male reproductive investment and success in zebra finches. We tested the hypothesis that males exposed to developmental stress sire fewer offspring through extra-pair copulations, but invest more in parental care. To test this hypothesis, we fed nestlings (F1) corticosterone (CORT; the dominant avian stress hormone) during the nestling period and measured their adult reproductive success using common garden breeding experiments. We found that nestlings (F2) reared by CORT-fed fathers (F1) received more parental care and were in better condition compared to nestlings reared by control fathers. Surprisingly, CORT-fed males (F1) also sired more offspring (F2) and were less likely to rear non-genetic offspring compared to control males. Contrary to the prediction that developmental stress decreases male reproductive success, we found that CORT-fed males had greater reproductive success in both the quality and quantity of offspring produced. In stressful environments, increased investment in parental care could maximize offspring survival and, hence, increase reproductive success. Alternatively, stressful developmental environments could increase senescence and trigger animals to invest more heavily in current reproduction (i.e. the terminal investment hypothesis).