Harper graduated magna cum laude from Brown University in 1988, with a BA degree in economics and sociology and was valedictorian of his department. In 1992, he graduated with a JD, cum laude, from Harvard Law School. He received an MPA degree with honors from John F. Kennedy School at Harvard University. During his years at Harvard, he was a full-time member of Boston's Black Folks Theater Company, one of the oldest and most acclaimed black theater troupes in the country.
While a student at Harvard, Harper befriended Barack Obama, with whom he played basketball. In 2012, Harper was appointed to The President's Cancer Panel, a three-member body assigned to work with the National Institutes of Health (NIH) and make recommendations to the White House around cancer policy.
He subsequently moved to Los Angeles to pursue acting. He has received eight honorary degrees, including honorary doctorates from both Westfield State College and Howard University.