He attended Bishop Hendricken High School in Warwick, Rhode Island.
He was drafted in the fourth round of the 2006 NFL Draft (115th pick overall) by the Green Bay Packers. He played college football for the Boston College Eagles. He has also played for the New York Giants, Seattle Seahawks, and Jacksonville Jaguars.
At Hendricken, Blackmon earned 2001 All-America first-team honors from United States of America Today, Entertainment and Sports Programming Network.com, SuperPrep and PrepStar as a senior.
Green Bay Packers
They were the first and second touchdowns of his career. In 9 games, he recorded 4 solo tackles and a pass deflected.
In the first game of his 2008 season with the Packers, Blackmon returned a punt 76 yards for a touchdown against the Minnesota Vikings. He was later named NFC Special Teams Player of the Week for games played September 4-8.
In week 10 of the 2008 NFL season, against the Minnesota Vikings once again, Blackmon returned a punt 65 yards for a touchdown.
Blackmon was released on an injury settlement from the Packers during 2010 roster cutdowns. New York Giants
Blackmon signed with the New York Giants on October 29, 2010. After being placed on injured reserve, the Giants waived Blackmon on January 2, 2011.
Then on November 23, 2011, after the Giants secondary got depleted with injuries, Blackmon re-signed with the team
He was released in the off-season and went on to play for the Arizona Rattlers of the Arena Football League. Seattle Seahawks
On February 13, 2013, Blackmon signed with the Seattle Seahawks.
He was released on August 27. Jacksonville Jaguars
On August 28, 2013, Blackmon was signed by the Jacksonville Jaguars.
He was released on February 26, 2015.
Second stint with Seahawks
On March 9, 2015, Blackmon signed a deal to return to the Seattle Seahawks. He was released for final roster cuts before the start of the season on September 6, 2015. Washington Redskins
Blackmon signed a one-year contract with the Washington Redskins on September 15, 2015.
After testing the free agency market for the 2016 offseason, Blackmon re-signed with the Redskins on a two-year contract on March 14, 2016.