The growing global energy demands, coupled with the imperative for sustainable environmental challenges, have sparked significant interest in electrochemical energy storage and conversion (EESC) technologies. Metal-free heteroatom-doped carbon materials, especially those codoped with nitrogen (N) and sulfur (S), have gained prominence due to their exceptional conductivity, large specific surface area, remarkable chemical stability, and enhanced electrochemical performance. The strategic incorporation of N and S atoms into the carbon framework plays a pivotal role in modulating electron distribution and creating catalytically active sites, thereby significantly enhancing the EESC performance. This review examines the key synthetic strategies for fabricating N, S codoped carbon materials (NSDCMs) and provides a comprehensive overview of recent advancements in NSDCMs for EESC applications. These encompass various electrochemical energy storage systems such as supercapacitors, alkali-ion batteries, and lithium-sulfur batteries. Energy conversion processes, including hydrogen evolution, oxygen reduction/evolution, and carbon dioxide reduction are also covered. Finally, future research directions for NSDCMs are discussed in the EESC field, aiming to highlight their promising potential and multifunctional capabilities in driving further advancements in electrochemical energy systems.