Joseph Case Pagliuca was born November 19, 1984, the eldest child of Stephen Gerard Pagliuca and Judy Pagliuca of Weston, Massachusetts. The Pagliuca family was, by the time Joe was old enough to remember, beginning to take its modern shape as one of the most prominent Boston business and basketball families of its generation. His father, Stephen, had graduated from Duke University in 1977 with a B.A., having played freshman basketball under coach Bill Foster (and a member of the 1973-74 Duke junior varsity team), then earned an MBA from Harvard Business School in 1982. By the time Joe was old enough to play organized basketball, Stephen had joined Bain Capital in 1989 and was building the private-equity career that would eventually make him Co-Chairman of the firm from 2016 to 2023. Stephen's brother Jeffrey had also graduated from Duke in 1977 — making two Duke '77 Pagliucas in Joe's immediate family pedigree.
The family Duke pipeline, in chronological order of arrival in Durham, would eventually run: Stephen '77 → Joe '07 → Stephanie '13 → Nick '17. Joe was the founder of his generation's leg of the pipeline. His sister Stephanie would later attend Duke (graduating 2013); his younger brother Nick would arrive at Duke a decade after Joe, walk on to Krzyzewski's program in fall 2013, take the same jersey number Joe had worn (No. 45), and play one minute of a 2015 Final Four that ended in a national championship. The other brother, Jesse, would not attend Duke but would carry the family name through the broader Boston business community.
Joe's basketball career began, as did his brother Nick's a decade later, in the Boston-area independent-school basketball ecosystem. He attended Belmont Hill School, the all-boys boarding school in Belmont, Massachusetts, just outside Boston — a school whose basketball program was respected within the Independent School League but had never, in its 80-year history, sent a player to a major Division I program on a basketball scholarship. As a three-year varsity letterwinner, Joe averaged 17.0 points per game as a senior and led the Belmont Hill Sextants to the semifinals of the New England Class A state tournament. He was named all-league in 2003. He also lettered one year in baseball.
The summer of 2003, between high-school graduation and his Duke arrival, captures something about the kind of family Joe had grown up in: he spent the summer working at a souvenir store next to Fenway Park. The son of one of Boston's most prominent business figures took a service-industry job adjacent to Boston's most beloved professional sports stadium — the older Pagliuca's later co-ownership of the Boston Celtics not yet on the family's books (Stephen would join Boston Basketball Partners' purchase of the Celtics for $360 million the same year, in 2003). Joe arrived in Durham in fall 2003 to begin his economics-major studies and to walk on to Mike Krzyzewski's basketball team.