Wearable and stretchable electronics have attracted tremendous attention due to their wide applications. One of the attractive solutions is the thermoelectric generators (TEGs), which can directly convert waste heat into electricity. To overcome challenges of traditional TEGs, ionic thermoelectric materials utilizing ionic transport open up new possibilities for the recuperation of waste heat. Herein, we introduce intrinsically stretchable acrylamide-based polymers comprising graphene derivatives, which possess high stretchability and excellent thermoelectric performance. Interestingly, thermopower could be tunable according to the molecular structure of graphene-based additives. The ionic thermoelectric performance was sustained during multiple stretch-release cycles, which demonstrates high durability under severe deformation. These findings show a promising strategy to obtain multifunctional ionic thermoelectric materials by engineering the molecular structures.