He is an alumnus of Dartmouth College, where he was a member of Beta Theta Pi fraternity. In football, Fiedler set school records for touchdown passes (58), passing yards (6,684) and total offense (7,249 yards).
Fiedler's stint with the Miami Dolphins featured three 10+ win seasons in four years, two 11–5 seasons in 2000 and 2001, an AFC East title, and two postseason appearances including a victory for the Miami Dolphins. During these years, the Dolphins' offense lagged notably behind its defense, which featured perennial Pro-Bowlers in linebacker Zach Thomas, defensive end Jason Taylor, and cornerbacks Sam Madison and Patrick Surtain.
Fiedler signed with the Jets as an unrestricted free agent on March 11, 2005, as a backup quarterback to Chad Pennington. On September 25, 2005, in a game against his former team the Jaguars, Fiedler was pressed into action when Pennington suffered what would prove to be a season-ending rotator cuff tear. Fiedler would himself suffer a severe shoulder injury during the game and was also sidelined for the remainder of the 2005 season.
Fiedler was released by the Jets on February 22, 2006, and signed with the Tampa Bay Buccaneers who released him in August of that year due to injury as Fiedler had a nagging shoulder issue and was unable to practice. Fiedler sat out 2006 rehabilitating his throwing shoulder following his release from Tampa Bay.
Fiedler was set to work out for the Falcons in April 2007, according to his agent Bryan Levy. In addition, the Giants considered signing him but eventually signed Anthony Wright instead.
Fiedler played in 76 games with 60 starts and is a 58.7 percent career passer. He has thrown 69 touchdowns and 66 interceptions.
Fiedler currently owns and operates The Sports Academy at Brookwood Camps and the Prime Time Sports Camps along with his brother Scott. Brookwood is a summer sleep away camp that has been family owned by the Fiedlers since 1986. Prime Time Sports Camps operates various sports camps and clinics throughout the year with Fiedler operating all of the football sessions.