In this research YSZ porous support and thin dense functional electrolyte layers are fabricated via a slip-casting method for fuel cell applications. The results show that calcination of YSZ starting powder is a crucial step in developing an effective porous structure having an interconnected void network for fuel cell applications. It is found that due to high surface area and high sinterability, as-received Tosoh YSZ powder is not a suitable candidate for production of interconnected porous structures even with the addition of pore former. Calcination at 1300–1500°C coarsens the YSZ powder and leads to the growth of particles to 15–100 μm. However, subsequent ball milling of the calcined powder for 72 h reduces the particle size to 400–800 nm (∼240 nm for uncalcined Tosoh YSZ) and increases the subsequent surface area, correlating with the temperature of calcination. With high-temperature calcination, it is possible to generate interconnected porous structures after sintering at temperatures lower than the calcination temperature. The bodies made of powder calcined at 1300°C become dense following sintering at 1350°C, which makes this material suitable as a dense fuel cell electrolyte. Using calcined powders, a multiple slip-casting procedure enables a dense electrolyte to be coated directly on a highly porous support. With this simple and inexpensive technique, high-quality strongly adhered YSZ layers can be engineered.