This study was aimed to understand the primary and secondary phytochemical profiles of Alternanthera sessilis and its influence on growth promotion of Macrobrachium rosenbergii. Complete extraction of A. sessilis leaf using petroleum ether (non-polar), followed by acetone (middle polar) and ethanol (polar) was performed first. Then the primary and secondary phytochemical profiles were studied. A. sessilis contains alkaloids, terpenoids, flavonoids, tannins, saponins, polyphenols, cardiac glycosides and quinones. GC-MS spectrum of A. sessilis revealed the presence of 17 secondary phytochemicals, totally. Among these, 5 compounds have possessed bioactive properties. Artificial feeds were prepared with incorporation of three different concentrations (0.1, 0.5 and 1%) of ethanolic extract of A. sessilis and fed to M. rosenbergii PL for 90 days. Among the three levels, 1.0% of ethanolic extract of A. sessilis incorporated feed produced the best growth performance, by showing the highest survival rate, weight gain and contents of total protein, amino acid, carbohydrate, lipid and ash, when compared with control, which was confirmed by the lowest food conversion rate. Thus, the present work recommends incorporation of A. sessilis as feed additive to attain sustainable culture of M. rosenbergii.