Casanova was born to Swiss-American immigrants, John and Marie Ursula Casanov on June 12, 1905 on a ranch in the Grizzly Bluff area near Ferndale, California. He got his start in football in the early 1920s when he played halfback for Ferndale High School, and in 1922 he captained the Ferndale team to a co-championship with Eureka High School. The Ferndale team ended the season with seven wins in eight games. One of Casanova’s early athletic feats came in the first game that year against Arcata High School when, as a left-footed kicker, he drop-kicked a 45-yard field goal as Ferndale defeated the Tigers, 10–0.