A chitinolytic actinomycete Streptomyces vinaceusdrappus S5MW2 was isolated from water sample of Chilika lake, India and identified using 16S rRNA gene sequencing. It showed in vitro antifungal activity against the sclerotia producing pathogen Rhizoctonia solani in a dual culture assay and by chitinase enzyme production in a chitin supplemented minimal broth. Moreover, isolate S5MW2 was further characterized for biocontrol (BC) and plant growth promoting features in a greenhouse experiment with or without colloidal chitin (CC). Results of greenhouse experiment showed that CC supplementation with S5MW2 showed a significant growth of tomato plants and superior disease reduction as compared to untreated control and without CC treated plants. Moreover, higher accumulation of chitinase also recovered in the CC supplemented plants. Significant effect of CC also concurred with the Analysis of Variance of greenhouse parameters. These results show that the a marine antagonist S5MW2 has BC efficiency against R. solani and chitinase enzyme played important role in plant resistance.