We investigate how the Madden-Julian Oscillation (MJO), the dominant mode of tropical subseasonal variability, modulates the life cycle of cool-season North Pacific atmospheric rivers (ARs), low-level jets of intensive poleward moisture transport. When the MJO convection is over the Indian Ocean, more AR events originate over eastern Asia and fewer originate over the subtropical northern Pacific. The opposite changes in the number and location of AR events appear when the MJO convection is over the western Pacific. Dynamical processes involving anomalous MJO wind and seasonal mean moisture are found to be dominant factors that impact AR origins. The anomalous geopotential height pattern of the MJO can modulate AR propagation directions. The robustness of these MJO-AR life cycle connections is further supported by model simulations. The modulation of AR life cycles by the MJO may help to further advance our understanding of subseasonal predictability and future changes of ARs.