Carbon materials have been playing a significant role in the development of alternative clean and sustainable energy technologies. This review article summarizes the recent research progress on the synthesis of nanostructured carbon and its application in energy storage and conversion. In particular, we will systematically discuss the synthesis and applications of nanoporous carbon as electrodes for supercapacitors and electrodes in lithium-ion batteries, and the development of nanoporous media for methane gas storage, coherent nanocomposites for hydrogen storage, electrocatalysts and catalyst supports for fuel cells, new porous carbon for lithium–sulfur batteries, and porous carbon for lithium–oxygen batteries. The common challenges in developing simple, scalable, and environmentally friendly synthetic and manufacturing processes, in controlling the nanoscale and high level structures and functions, and in integrating such materials with suitable device architectures are reviewed. Possible new directions to overcome the current limitations on the performance are discussed.