Grew up in Syracuse, New York and attended Bishop Ludden High School. In the winter, Kevin mostly focused on basketball but would occasionally go to an indoor golf practice facility at Turning Stone Resort Casino, which was about 45 minutes from home.

As a senior at Long Beach State University, Kevin played the 2011-12 season alongside true freshman Xander Schauffele. Roy led the team in scoring average that year (72.42), while Schauffele was second (72.52), and the duo led the team to five tournament wins, which set a single-season program record.

Credits his father, Jim Roy, as his biggest golf influence and supporter. Jim played a full PGA TOUR season in 1983 and a full PGA TOUR Champions season in 2010. Jim notably qualified for two U.S. Opens (1983, 1989), three U.S. Senior Opens (2010, 2018, 2022), and the 2010 Senior PGA Championship. Jim played collegiately at University of South Florida in Tampa and was inducted into the Greater Syracuse Sports Hall of Fame in 2007.

One of his biggest thrills was caddying for his dad in the U.S. Senior Open in 2018.

One of his favorite golf memories was making his first hole-in-one at age 16; he made the ace with his friend's iron.

Older brother, Kyle, played college golf at NCAA Division II Tampa University (2007-11).

Father-in-law, Chris Sabo, played third base for the Cincinnati Reds (MLB) and was the 1988 National League Rookie of the Year, a three-time All-Star, 1990 World Series champion, and Reds Hall of Famer.