There are provided a piezoelectric actuator, an inkjet head assembly, and a method of manufacturing the same. The piezoelectric actuator includes: upper and lower electrodes providing driving voltage; and a piezoelectric substance formed between the upper and lower electrodes through solidifying a liquid piezoelectric substance, and providing driving force to ink in each of a plurality of pressure chambers provided in an inkjet head, wherein the piezoelectric substance includes a plurality of branch portions individually provided on an upper portion of each of the plurality of pressure chambers and a large area portion integrally provided while being connected to each of the plurality of branch portions at one ends of the plurality of branch portions.