The densification of a Sr, K, Nb (SKN)-doped PZT ceramic has been modified using different flux chemistries. The most successful flux is Li2CO3 of which a 0.9 mol% addition promotes almost complete densification at 900°C. Structure property relationships in the Li2CO3 flux-sintered (1−x)PZT–xSKN system (0.01<x<0.05) are compared with conventionally sintered material. Consequences of flux interactions include increased conductivity and a shift in the optimum (1−x)PZT–xSKN composition. The flux sintered PZT–0.03SKN composition exhibits a high field d33 piezoelectric coefficient of 640 pm/V and a Curie temperature of ∼350°C. The unipolar polarization hysteresis loss is ∼23 kJ/m3 and varies little with temperature up to 150°C. Finally, we demonstrate successful cofiring of a multilayer structure at 900°C using Li2CO3-fluxed PZT–SKN and pure silver electrodes.