Coastal brackishwater resources are highly fertile, rich in biodiversity and provide livelihood to traditional fisher families. However, due to natural disturbances and manmade interruptions, its fishery resources are depleted, hence, the livelihoods of dependent fishers are threatened. Aquaculture of fishes in customized cages and pens is a proficient approach for the efficient utilization of this productive natural resource. In this context, a three-tier cage farming system of Asian Seabass fish (Lates calcarifer) comprised of a nursery, pre-grow out and grow-out phases was developed and validated for its techno-economic viability with the participation of fisher folk. The technical indicators viz., fish survival, feed conversion, growth rate, productivity, economic parameters viz., Benefit Cost Ratio, Pay-back period and Internal Rate of Return and the livelihood security pointers have substantially shown that the system is technically feasible, economically viable, socially acceptable and hence, sustainable. Planned interventions in the form of appropriate policy guidelines to undertake community involved cage aquaculture in the coastal brackishwaters, a scheme for periodical flushing of bar mouths to ensure connectivity with the sea, institutional credit and insurance support are outlined to up-scale the adoption of cage farming technology in the brackishwaters across the coastal states of India. It is a win-win approach for the efficient utilization of coastal brackishwaters for augmenting fish production and enhancing the livelihood security of coastal fishers.