The design and operation of a pulsed high‐power narrow‐line CH3F oscillator‐amplifier laser system is described. The dielectric waveguide oscillator produces output in a single longitudinal mode with linewidth less than 40 MHz and sufficient power (∼11 kW) to saturate the far‐infrared emission transition at the amplifier input. Pumped by ∼8 J of CO2, the amplifier has produced up to 156 kW of narrow‐line 496‐&mgr;m output. The amplifier gain is found to be sensitively dependent upon the relative timing of the FIR oscillator and CO2pump pulses.