At Catholic High in Baton Rouge, Louisiana, Dunn played quarterback, cornerback, and running back. During his junior year he helped lead Catholic High to the state 4A championship game for the first time in its history. He was an All-America honorable mention selection by USA Today as a senior.

Dunn enjoyed a successful college career at the Florida State University, graduating in 1997 with a bachelor's degree in information studies. He holds several Florida State rushing records including the marks for most career rushing yards (3,959) and most rushing yards in a season (1,242) set in 1995. Dunn is the only Seminole to rush for over 1,000 yards in three consecutive seasons. He was a three time All-ACC selection and a member of

Dunn's jersey, along with those of other Seminoles players such as Fred Biletnikoff, Ron Sellers, Ron Simmons, Charlie Ward, Deion Sanders, and Chris Weinke, has been retired by the university. His number, 28, may still be worn by Seminole players, but his jersey will be displayed in the Moore Athletic Center at FSU. He also won a National Championship in 1993 with Florida State.

Dunn was selected in the first round of the 1997 NFL Draft with the 12th overall pick by the Tampa Bay Buccaneers. In his rookie season Dunn made an immediate impact for the Buccaneers squad. As the year finished he was selected to the NFC Pro Bowl team and was named the Associated Press Offensive Rookie of the Year. Dunn spent the first five years of his career in Tampa Bay where he was named to the Pro Bowl twice (1997,2000) before signing with the Atlanta Falcons in the 2002 off-season. Once again, he made a positive impact on his team with 9 total TDs and in that year, he led the league with a 5.4 yards per carry average. Dunn scored the most rushing touchdowns in his career, 9, in the 2004 season despite splitting carries with T.J. Duckett and also led the team in rushing with 1,106 yards. Having led his team in rushing yards again in 2005, Dunn was named the NFC's Pro Bowl team, marking his third selection to the team. For his career, Dunn has only missed 10 games and has a total of 2,256 carries for 9,461 yards 43 touchdowns and a 4.2 average.

Dunn established the Warrick Dunn Foundation and the Homes for the Holidays program, which helps struggling single mothers purchase homes. The program buys homes through a down payment provided by Dunn, who also worked with area sponsors to furnish and outfit the homes. The program, as of 2004, has assisted roughly 45 single mothers and 120 children in Atlanta, Baton Rouge, and Tampa, Florida. Dunn's goal is help these mothers realize the dream that his mother was not able to give to him and his siblings, to own their own home. Dunn's achievements have been recognized over the years. He received a Giant Steps Award in civic leadership from former President Bill Clinton for his program. In 2005, Dunn was presented with the Walter Payton Man of the Year Award; named after the Chicago Bears running back who died in 1999, the award is the only NFL award that recognizes a player for his community service as well as for his excellence on the field. In the aftermath of Hurricane Katrina, Dunn challenged all NFL players, except for those who play for the New Orleans Saints, to donate at least $5,000 to the effort. Since forming his foundation, Dunn has received over $5,000,000 in contributions.

Dunn created a music production company in Atlanta, where he has signed several acts. His only major rule is that the music is not allowed to glorify violence. He is also the owner to two sporting goods stores, one in Tallahassee, the other in Atlanta.