The output performance of the electron‐beam‐excited KrF laser operating at one atmosphere is theoretically analyzed because the KrF laser at one atmosphere can greatly reduce the design constraints on the large laser windows and the electron‐beam pressure foils in a huge laser system as the inertial confinement fusion energy driver. The KrF laser using the atmospheric pressure, argon‐free laser mixture is found to operate with an intrinsic laser efficiency as high as that of high‐pressure, aregon‐diluted mixtures. This is because three‐body collisional quenching is not a detrimental energy‐loss channel for the atmospheric pressure operation. By using higher excitation rate and shorter excitation pulse width pumping, higher intrinsic laser efficiency than conventional, argon‐diluted, high‐pressure mixtures is found to be attainable. Moreover, the specific laser energy (28 J/l, for 1‐atm Kr/F2mixtures pumped by an electron beam of 100 ns, 600 keV, and 150 A/cm2) is comparable to that of two‐atm, argon‐rich laser gas mixtures under the same excitation condition.