The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system uses advanced coronagraphic technique for high contrast imaging of exoplanets and disks as close as 1 lambda/D from the host star. In addition to unusual optics, achieving high contrast at this small angular separation requires a wavefront sensing and control architecture which is optimized for exquisite control and calibration of low order aberrations. The SCExAO system was thus designed to include the wavefront sensors required for bias-free high sensitivity and high speed wavefront measurements. Information is combined from two infrared wavefront sensors and a fast visible wavefront sensors to drive a single MEMS type deformable mirror mounted on a tip-tilt mount. The wavefront sensing and control architecture is highly integrated with the coronagraph system.