Denny began his baseball career at the age of ten when he joined the Port Huron Little League. In 1959 while pitching for Local 44, Denny threw the first no-hitter in Port Huron Little League history. At the age of thirteen, Denny moved up to Babe Ruth where he was selected to the All-Star team twice and closed out his Babe Ruth career with a .656 batting average. Denny starred in baseball at Port Huron High School. He also played on two championship teams at Port Huron Junior College before earning a scholarship and playing at the University of Kentucky where he was the team's leading hitter with a .370 average his senior year. After graduating from college, Denny came home to begin a successful softball career playing both fast pitch and modified.