This article examines the development and transformation of the holy spirit within Jewish mysticism. It begins with a brief analysis of primary trends concerning the holy spirit in biblical, rabbinic, and medieval Jewish texts that served as crucial material for the holy spirit's ascendence in sixteenth-century Jewish mysticism. Following, it examines the writings of leading Jewish mystics: Moses Cordovero, Elijah de Vidas, and Hayyim Vital, who resided in the remote Galilean town of Safed. These luminaries each developed the concept of the holy spirit along a spectrum of pneumatic, fusionary, mystical, and revelatory experiences. Ultimately, they transformed the holy spirit into the peak experience of Jewish mystical life- experienced as prophecy, sanctification, and embodiment. This article highlights an important, yet understudied, Jewish mystical phenomenon.