Porous carbons derived from microalgae were prepared using a pyrolysis method. The microstructure and electrochemical performance were studied using X-ray diffraction, Raman spectrometer, scanning and electron microscopy techniques. The electrochemical performance was investigated using electrochemical methods. A carbon sample pyrolyzed at 900°C exhibited a hierarchical pore structure with a large amount of microcrystalline graphitic domains. As a result, this sample delivered the best electrochemical performance with specific charge capacities of 445mAhg−1 at 0.1C and 370mAhg−1 at 1C, respectively. In addition, this sample showed a capacity retention of 95% after 500 cycles at 1C. The good electrochemical performance of the pyrolytic carbon is attributed to the combined contributions of the hierarchical porous structure and microcrystalline graphitic carbon domains.