<p>Global temperature increases due to anthropogenic greenhouse gas (GHG) emissions pose a significant threat to both the environment and agricultural productivity. Biochar, a carbon-rich byproduct produced from plant and animal biomass through pyrolysis, has emerged as a potential tool for mitigating GHG emissions and sequestering carbon in soils. However, the effectiveness of biochar in this regard is influenced by various factors, including the type of feedstock used. This research aimed to investigate the impact of plant-based and animal-based biochar on GHG emissions and carbon sequestration potential in submerged soils. Rice and barley straws were selected as representative plant-based feedstocks, while cow and swine manures were chosen to represent animal-based feedstocks. An incubation experiment was conducted to evaluate the performance of biochar derived from these different sources. The results revealed that feedstock type significantly influenced the GHG mitigation and carbon sequestration potential (CSP) of the biochar. Plant-based biochar revealed approximately 37% higher CSP compared to animal-based biochars and decreased the net global warming potential (GWP) by approximately 39–41% compared to the control, while animal-based biochar achieved a reduction of only 20–26%. This study provides valuable insights into the role of feedstock type in determining biochar’s effectiveness in mitigating GHG emissions and sequestering carbon. These findings contribute to the broader understanding of sustainable practices for reducing GHG emissions and enhancing carbon storage in soils. Therefore, carefully considering the biomass feedstock type is crucial when selecting biochar for these purposes. Notably, plant-based biochar proved to be more effective than animal-based biochar in reducing GHG emissions in submerged soils.</p>