This study assessed the processing suitability and functional potential of sweet potato paste by comparing quality characteristics across different cultivars and heat treatment methods (steaming and baking). Generally, moisture content was higher after steaming, with the ‘Bodami’ and ‘Pungwonmi’ cultivars retaining more moisture, while ‘Jinyulmi’ and ‘Danjami’ had lower moisture levels. Purple-fleshed cultivars displayed negative a* and b* values, indicating bluish hues, whereas yellow-fleshed cultivars maintained stable b* values after heating. Both °Brix and free sugar levels increased after treatment, with baking significantly elevating maltose levels and enhancing sweetness. Apparent viscosity was higher in ‘Danjami’, ‘Jinyulmi’, and ‘Bodami’, while ‘Hogammi’, ‘Hopungmi’, and ‘Sodammi’ exhibited lower viscosity. Additionally, ‘Bodami’ and ‘Danjami’ demonstrated the highest levels of polyphenols, flavonoids, and antioxidant activities, confirming their potential as valuable functional ingredients. These findings underscore the importance of selecting appropriate cultivars and heat treatments to optimize the physicochemical and functional qualities of sweet potato paste.