Paul was born in Colon Matanzas, Cuba in 1941. He was one of four boys raised in the Casanova family. As a young boy, playing baseball was a common part of his daily routine. In his teenage years he sought to play semi-pro-ball in Cuba. He worked his way into this competitive level of play and from that point forward, chased his dreams to play in the Majors.
In 1960, the Cleveland Indians were in Paul's hometown searching for local talent. All eyes were focused on Casanova's commanding presence behind home plate. He was brought to the United States that same year to play ball for the Indians. He was a part of the organization most of one season and was than released. In 1961, Paul was presented the opportunity to catch for the Indianapolis Clowns. These were the very Clowns that occupied a spot in the Negro American League for so long, only now they had relinquished their affiliation to become an Independent team. This experience would turn out to be quite an enjoyable one for Paul, but it would also be his last full season of baseball for some time. In an effort to make a living, Casanova decided to put baseball aside, and pursue a career as a tradesman in the construction field.
Playing with the Negro Leagues was in and of itself satisfying, but being exposed to the professional scouting personnel throughout his early playing days would prove to be an added bonus. It seemed the Washington Senators staff had a particular interest in the Indianapolis Clowns Organization. Senators scout, John Caruso remembered Paul well, and for nearly three years hunted him down and directed his attention back to the baseball diamond. John truly believed in Casanova's potential and brought him into the Senators training Camp for a try-out. He had only a few days to prove himself in the minors, as the camp was already quite full. He was slated to be a second string catcher and as fate would have it, their first string starting catcher broke his leg at the start of the season while running to first base. This injury was so severe that he would be unable to play. This was a huge break for Casanova as he was called upon to fill the vacancy behind the plate.
In 1965, he was called up to the Washington Senators major league team. His career in the majors produced some of his greatest baseball memories. It was in 1968 that this Washington Senators catcher played in the game that has since that day been recorded the longest night game ever played in the major leagues. Paul emerged a hero that night as he stroked the game winning single in the 22nd inning.
Several years later, halfway through the 1971 season, the players were informed that the Senators would be moving to Texas. This news disturbed Paul as it did many of the players. They had enjoyed many great years in Washington. Casanova was subsequently traded to Atlanta Braves in 1971, where he would team up with and befriend another former Negro Leaguer, Indianapolis Clown veteran - Hank Aaron. Aaron hit his 715th home run that year and Paul witnessed his teammate catch that ball from the dugout, two games later Paul would catch Aaron's 716th homerun making Hank the MLB home run leader.
Currently Paul and fellow NLB Living Legend Panchon Herrera are working with Chico Fernandez to start a baseball academy within the Miami, Florida community.