A watt-level output passively mode-locked Tm:LuAG bulk laser with an InGaAs semiconductor saturable absorber mirror (SESAM) is demonstrated for the first time. A maximum average output power of 1.21 W at 2022.9 nm has been achieved with a pulse duration of 38 ps and a repetition rate of 129.2 MHz. The results indicate the potential of Tm:LuAG crystals as candidate for realizing high power ultrafast lasers at 2 μm.