Fleming attended Stratford High School, where he was the starting quarterback in football. He was the starting power forward in basketball. He also practiced track and field.
Fleming accepted a scholarship from the University of Tennessee and was converted to wide receiver. As a sophomore, he scored five touchdowns out of just 14 receptions, contributing to the team winning the SEC championship. After being the backup to Carl Pickens, he became a starter as a junior, registering 40 receptions for 490 yards (leading the team) and two touchdowns. In his last year, he posted 39 receptions for 596 yards and 11 touchdowns.
Fleming finished his college career with 94 receptions for 1,266 yards, and at the time school records, with 18 career touchdown receptions, 11 single-season career touchdown receptions, and six consecutive games with a touchdown reception.
Fleming was selected by the San Francisco 49ers in the third round (87th overall) of the 1994 NFL Draft. On July 21, the team rescinded his rights because of salary cap reasons, making him a free agent.
On August 3, 1994, he was signed by the Dallas Cowboys. The next year, he competed to replace Alvin Harper in the starting lineup, but lost out to Kevin Williams and was named the team's third wide receiver, making him a part of the Super Bowl XXX winning team.
In 1996, he was released on February 6 and was also suspended for a year by the NFL after failing a third drug test.
In 1997, he was signed by the Nashville Kats of the Arena Football League, after being contacted by then offensive coordinator Jay Gruden. In 10 seasons, he was a five-time All-Arena, a four-time All–Ironman and an Ironman of the Year selection.
In 2013, Fleming was inducted into the Arena Football Hall of Fame.
Fleming owns an insurance agency and also organizes football camps for kids in the offseason. In August 2013, he was arrested in Davidson County, Tennessee, for driving under the influence of alcohol.