Scott played for Coach Stu Vetter at Flint Hill in Oakton, Virginia. Flint Hill Prep finished ranked #1 in the nation Dennis' senior year ('87) as ranked by USA Today. In his junior year at Flint Hill Prep, his team finished ranked 2nd in the nation by USA Today and 1st as ranked by Blue Ribbon yearbook. Given his size, strength, shooting ability, and quickness Dennis played every position at one time or another during his high school career.
Scott spent the majority of his career with the Magic, earning the nickname 3-D for his ability to consistently make long three-point field goal attempts. Until the drafting of Shaquille O'Neal in 1992, Scott and Nick Anderson were the leading scorers for the Magic. In 1995–96 Scott set an NBA single-season three-point field goal tally with 267 (which was broken ten years later by Ray Allen). He also set the NBA record for most three pointers made in a single game with 11 on April 18, 1996. On his record breaking shot the assist came from teammate and the holder of the record, Brian Shaw (he made 10 three pointers on April 8, 1993). This record has also since been broken by Kobe Bryant who made 12 three pointers on January 7, 2003 and by Donyell Marshall who also made 12 three pointers on March 12, 2005. He was honored by the Magic on March 26, 2006 as part of their "Remember the Past Nights" program, where the Magic remembers past players for their accomplishments. Other players to be honored so far were Nick Anderson and Scott Skiles. In 2008, Jay Bilas ranked his personal top 25 threepoint shooters in NCAA history and Scott was #1 on his list.