Cascaded　mid-infrared　(MIR)　pulsed　laser　output　in　Er:YAG　crystals　at　room　temperature　is　achieved　experimentally.　The　existence　of　a　cascade　at　room　temperature　in　Er:YAG　crystals　is　confirmed.　Furthermore,　the　effect　of　the　cascade　on　MIR　laser　performance　is　studied.　With　the　assistance　of　the　cascade,　the　thresholds　are　reduced　by　13.3%　and　12.5%,　and　the　slope　efficiencies　are　increased　by　3.2%　and　12.3%　compared　to　a　non-cascade　configuration　in　10　and　15　at.%　Er:YAG,　respectively.　The　excited-state　absorption　is　considered　to　be　the　mechanism　responsible　for　the　laser　performance　optimization.　This　Letter　should　be　helpful　for　the　improvement　of　erbium-doped　3　mu　m　laser　output　energy.　(C)　2021　Optical　Society　of　America