Dahl was an all-state selection at Churchill County High School; he was named all-league and All-Northern Nevada. Dahl also was a three-time zone wrestling champion and state champion at 215 lbs. in 1999. His #59 number was retired by Churchill County in January 2009.
Dahl signed with Dallas on April 28 after he went undrafted in the 2005 NFL Draft. He was waived on June 3.
San Francisco 49ers
He was claimed by San Francisco off waivers from Dallas on June 8, 2005. Dahl was waived on August 30 but signed to the practice squad on September 5. Dahl signed to the 53-man roster from the practice squad on December 20 and was allocated by San Francisco to NFL Europe Rhein Fire on January 11, 2006. He played in his first professional game against the St. Louis Rams.
Atlanta Falcons
Dahl was signed by the Falcons off the San Francisco practice squad to the active roster on October 9, 2007, after the Falcons placed Wayne Gandy on injured reserve. In 2008, he became a full-time starter for the Falcons at right guard. He established a name for himself as one of the league's toughest, nastiest players. He also helped pave the way for the Falcons' Pro Bowlrunning backMichael Turner and the Falcons' run game, which was second in the league in rushing. Dahl excelled in pass blocking as well, as he and the rest of the Falcons offensive line only allowed 17 sacks of 2008 AP Offensive Rookie of the Year quarterback Matt Ryan. During the Falcons–49ers match-up on October 11, 2009, Dahl and San Francisco head coach Mike Singletary got into a spat on the field where Singletary told Dahl, "You better be happy you didn't play back in my day! If I could see you on the field!..." to which Dahl replied, "Suit up, then!"
St. Louis Rams
Dahl was signed to a contract by the Rams on July 29, 2011. Details of the contract were undisclosed. In a game against the Cincinnati Bengals on December 18, 2011, Dahl was penalized for holding. He yelled "That's not fucking holding!" into referee Jerome Boger's open microphone as Boger was announcing the holding penalty to the crowd. As a result, the expletive was heard throughout the stadium and on television. Boger further assessed an unsportsmanlike conduct penalty on Dahl and Dahl later apologized for the incident. CBS color commentator Dan Dierdorf apologized on-air because Dahl’s fleeting expletive slipped past the CBS censors. The incident re-introduced discussion as to installing a delay in live NFL broadcasts of a few seconds to allow for censorship of unacceptable language or incidents. On March 10, 2014, Dahl was released by the Rams.
