Flint is a 1987 graduate of Saint Joseph's University. While attending St. Joe's, Flint was a member of the school's varsity basketball team. Flint was named to the all-Atlantic 10 team as a senior, and was inducted into the St. Joe's athletic hall of fame in 1988.
In 1987, Flint became an assistant coach at Coppin State University. Two years later, Flint became an assistant coach under John Calipari at the University of Massachusetts Amherst (or UMass). After Calipari left UMass for the NBA in 1996, Flint was named his successor, becoming the school's 17th head coach. While coach of the Minutemen, Flint compiled an overall record of 86–72, including a 52–28 in-conference record. He won an NABC District Coach of the Year award in 1998. Facing pressure after being unable to maintain the Minutemen's level of success that they enjoyed under Calipari, Flint resigned from UMass after the 2000–01 season.
Flint became the head coach at Drexel on April 5, 2001, succeeding Steve Seymour, who had been fired that March after failing to make the NCAA Tournament in either of his two seasons as head coach. Flint's hiring at Drexel coincided with Drexel's move from the America East Conference, where the school had enjoyed a sustained level of success under former head coach Bill Herrion, to the Colonial Athletic Association (or CAA).
During his tenure at Drexel, Flint has been named CAA coach of the year four times (2002, 2004, 2009, 2012). He also won an NABC District Coach of the Year award three times (2007, 2009, 2012). Under Flint, Drexel has made five NIT appearances. In 2012, the school won its first CAA Regular Season Championship in 2012, but lost to VCU in the finals of the Conference Tournament. On Selection Sunday, Drexel narrowly missed an at-large berth in the NCAA Tournament.
National champion Postseason invitational champion Conference regular season champion Conference regular season and conference tournament champion Division regular season champion Division regular season and conference tournament champion Conference tournament champion