Seaweed is a resilient macrophytic plant thriving in intertidal zones. These are rapidly gaining attention due to their autotrophic nourishment, rapid growth, and minimal land requirement for cultivation. Seaweed is used in various food and non-food sectors, thus possessing immense potential as a valuable bioresource with high commercial value. However, utilizing seaweed as a bioresource comes with various challenges at processing levels, particularly at cost-effective downstream processing. Hence, this review highlights the advancement in seaweed biomass processing together with its application in food, nutraceuticals, pharmaceuticals, cosmetics, and non-food sectors. Additionally, the advancements in seaweed cultivation and the applications of seaweed in agriculture as a biostimulant, biofuel production, and packaging material are also reviewed. Finally, this review addresses the need for technology intensification, public awareness, and financial investment to enhance the commercialization and integration of seaweed-based products into the bioeconomy. The potential of seaweed to contribute to climate change mitigation and the circular economy is underscored, calling for further research and development to optimize its multifaceted applications.