Howard Walter Cannon was born on January 26, 1912 in St. George, Utah to Walter and Leah Sullivan Cannon. He grew up on a ranch in southwest Utah and graduated from Dixie Junior College in St. George. Cannon also attended Arizona State Teachers College in Flagstaff, Arizona where he received his bachelor's degree in 1933. The following year he enrolled at the University of Arizona where he earned a law degree in 1937. Cannon returned to St. George, passed the state bar examination, and established a law practice.