On the post-secondary level, he attended Wofford College, Stetson University, and graduated from the University of Miami School of Law in 1931.
He was admitted to the bar in 1931, and commenced practice in Miami, Florida. Cannon was elected as a Democrat to Florida"s 4th District in the United States House of Representatives for the Seventy-sixth Congress, and to the three succeeding sessions of the United States Congress (January 3, 1939 – January 3, 1947). He was an unsuccessful candidate for renomination in 1946.
After leaving Congress, Cannon resumed the practice of law and was elected circuit judge of Dade County, Florida in 1952.
He was reelected in 1954 and in 1960 to six-year terms. Cannon was a resident of Miami, Florida until his death in Miami on January 23, 1966.
Cannon was interred in Woodlawn Park Cemetery (now Caballero Rivero Woodlawn North Park Cemetery and Mausoleum), Miami, Florida.