Just days after the 2007 BCS National Championship Game, Caldwell announced he would return to Florida for his senior season. As a senior team captain in 2007, Caldwell recorded a career-high 761 yards and seven touchdowns on fifty-six receptions, had twelve carries for fifty-eight rushing yards and a touchdown, and was the recipient of the Gators' Fergie Ferguson Award as the "senior football player who displays outstanding leadership, character and courage." Caldwell finished his senior season with 100-yard receiving games against the Western Kentucky Hilltoppers, Vanderbilt Commodores, South Carolina Gamecocks, and Florida Atlantic Owls. His 185 receptions in his four-year college career remains the best career total in Gators history.
Caldwell graduated from the University of Florida with a bachelor's degree in sociology in December 2007.