Sintering of potassium-sodium niobate (KNN) is troubleshot due to the presence of volatile oxides and sintering temperatures approaching the melting point of KNN. To overcome this problem, here using the powders produced by the solid-state synthesis route were sintered via different novel sintering techniques such as cold sintering process (CSP), ultra-fast high-temperature sintering (UHS), fast firing (FF), and the results were compared with conventional sintering. Dielectric, ferroelectric, and piezoelectric properties of the monolithic samples were also determined. While each process demonstrated a different densification degree, the tablets exhibited different electrical properties, especially ferroelectric properties, with other anomalies.