In the marine environment, algae are regarded as globally distributed entity. The excessive accumulation of nutrients such as nitrogen or phosphorus causes an algal bloom, which is caused by the rapid growth of microscopic algae rather than macroscopic ones. Even though it has negative effects, its significance in terms of biological usage was limited to experimental perspective. In our study, we have utilized algal waste biomass of Trichodesmium erythraeum to valorize its natural metabolites for the vector control, bacterial inhibition and anticancer study. Among the solvents, the methanolic extract produced significant mosquitocidal action against A. stephensi, A. aegypti, and C. quinquefasciatus. The methanolic extract of T. erythraeum were found to inhibit the growth of clinical pathogens including B. subtilis, P. mirabilis, S. aureus, E. coli and K. pneumoniae. Further, the methanol extract mediated anticancer effect was assessed on non-small cell lung cancer cell lines. Moreover, the extract displayed no impact on non-target organism. FT-IR results suggested the incidence of alkanes (–C ≡ C–H: C–H stretch), nitrile (C ≡ N), (primary amines (N–H bend), aliphatic amines (C–N stretch), alkenes (= C–H bend) and nitro compounds (N–O asymmetric stretch). GCMS analysis listed the series of compounds such as Hexadecanoic acid, Bicyclo [10.1.0] tridec-1-ene, Glycidol stearate, Tricyclo [20.8.0.0 (7, 16)] triacontane, 1(22), 7 (16)-diepoxy- and Piperidine played vital role in vector control and bactericidal action. This study specifies on usage of algal metabolites and the obtained results imply that it might be useful for essential medicinal applications.