Cooper Flagg’s parents are Kelly and Ralph Flagg. Kelly (née Bowman) played college basketball at the University of Maine, where she served as team captain during her senior year. Ralph competed in NJCAA basketball at Eastern Maine Community College. The couple has three sons:
- Hunter Flagg: The eldest son, Hunter, was a basketball player at Nokomis Regional High School in Maine. Born prematurely, he weighed just 1 pound, 10 ounces at birth. Hunter is currently a senior at Nokomis.
- Ace Flagg: Cooper’s twin brother, Ace, also played basketball at Nokomis before transferring to Montverde Academy in Florida. Ace has verbally committed to play at the University of Maine starting in the 2025–26 season.
The Flagg family hails from Newport, Maine, and has a strong basketball lineage. Cooper and Ace’s parents met while playing basketball in a men’s league at a community center, bonding over their shared love for the game. Their dedication to basketball has significantly influenced their sons’ athletic pursuits.