A step-in binding system (20) for securing a boot (24) to a snowboard (22). The boot includes a sole defining a toe end, a heel end, and a binding attachment surfaces (46 and 50). The boot also has an elongate, substantially U-shaped highback (28) mounted to the exterior of the boot in the calf area thereof and extending from the ankle area to the top of the boot. The step-in binding system includes a toe and heel binding (62 and 64) attached to the snowboard for receiving and securing the boot to the snowboard. The step-in binding system also includes a lever arm (66) attached to the heel binding for selectively releasing the boot from the binding. A lean support member (68) is fastened near the rearward end of the binding for engagement with a stopper block (29) secured to the highback to define a minimum forward lean angle of the boot and to limit the aft flexure of the ankle support portion of the boot when the boot is received within the binding.