Pike was elected as bishop coadjutor of California in 1958 and succeeded to the see a few months later, following the death of his predecessor, Karl Morgan Block, to become the fifth Bishop of California. He served in this position until 1966, when, plagued by personal loss, absorbed with the paranormal, tired of diocesan attacks, wrangling and administration, and exhausted from hyperactivity, he resigned his office to become a senior fellow for the Center for the Study of Democratic Institutions in Santa Barbara, California, a liberal think tank founded by Robert Maynard Hutchins, where he began an extensive schedule of speaking engagements. During this period, he was an adjunct professor at the University of California, Berkeley, School of Law (1966–1967) and the Graduate Theological Union (1966).