Walter J. Zable was born in Los Angeles, California. However, he grew up in Boston, Massachusetts during the Great Depression while his father worked as a mill worker. Before Zable even reached high school he had already taken a keen interest in electronics. During the daytime he would work on his athletic ability—specifically his football, baseball and track and field prowess—and at nighttime he was enrolled in Boston Trade School where he would take classes at Massachusetts Institute of Technology and Wentworth Institute of Technology. Years later Zable recounted that "electronics and athletics were [his] life." He graduated from high school in 1933.