A closure assembly with a shape memory polymer seal is provided for use with a vehicle. The closure assembly includes a frame member configured for attachment to the vehicle body to selectively transition from a closed position to an open position. The seal structure includes a base portion elongated along and attached to a peripheral edge of the frame member or the vehicle body, and a flexible contact portion extending integrally from the base portion and configured for sealing communication with an opposing surface. A thermally-activated smart material (TASM), namely a shape memory polymer member, is disposed inside a cavity within the contact portion. A thermoelectric device is in thermal communication with the TASM, and is characterized by a thermal differential when current flows therethrough. The TASM is activated in response to the thermal differential of the thermoelectric device, thereby altering at least one physical property of the TASM.