High-energy X-ray and ultraviolet (UV) radiation from young stars impacts planetary atmospheric chemistry and mass loss. The active ~22Myr M-dwarf AU-Mic hosts two exoplanets orbiting interior to its debris disk. Therefore, this system provides a unique opportunity to quantify the effects of stellar X-ray and UV irradiation on planetary atmospheres as a function of both age and orbital separation. In this paper, we present over 5hr of far-UV (FUV) observations of AU-Mic taken with the Cosmic Origins Spectrograph (COS; 1070-1360{AA}) on the Hubble Space Telescope (HST). We provide an itemization of 120 emission features in the HST/COS FUV spectrum and quantify the flux contributions from formation temperatures ranging from 104 to 107K. We detect 13 flares in the FUV white-light curve with energies ranging from 1029 to 1031erg/s. The majority of the energy in each of these flares is released from the transition region between the chromosphere and the corona. There is a 100x increase in flux at continuum wavelengths {lambda}<1100{AA} in each flare, which may be caused by thermal Bremsstrahlung emission. We calculate that the baseline atmospheric mass-loss rate for AU-Micb is ~108g/s, although this rate can be as high as ~1014g/s during flares with L_flare_~10^33^erg/s. Finally, we model the transmission spectra for AU-Micb and c with a new panchromatic spectrum of AU Mic and motivate future JWST observations of these planets.