After four years at
Villanova University Allen went undrafted in the
2000 NBA draft. He began his career in the ABA with the
San Diego Wildfire and in the International Basketball League with Trenton in 2000–01 season. On July 20, 2001, he was signed by the
Miami Heat of the
NBA. He stayed with the
Heat until he was traded on February 24, 2005, to the
Charlotte Bobcats. The
Chicago Bulls signed him to a two-year deal on September 2, 2005. Over two seasons with the
Bulls Allen played in 114 regular season games making 21 starts and averaged 4.5 points and 2.3 rebounds per game. On September 10, 2007, the
New Jersey Nets signed Allen to a one-year contract worth US$964,636. Allen appeared in 21
NBA Playoff games. He started all six playoff games for
Chicago during '06 playoffs. On February 19, 2008, he was traded to the
Dallas Mavericks along with
Jason Kidd and
Antoine Wright in exchange for
Keith Van Horn,
Devin Harris,
Trenton Hassell,
DeSagana Diop,
Maurice Ager, $3 million cash and
2008 and the Mavericks' 2010 first round draft pick. On July 17, 2008, he, along with
Tyronn Lue of the
Dallas Mavericks, signed a contract with the
Milwaukee Bucks. On July 22, 2009, the
Denver Post reported that he was set to be traded to the
Denver Nuggets in exchange for
Sonny Weems and
Walter Sharpe. The trade was made official on July 31, 2009. On September 16, 2010, the
Orlando Sentinel reported that Allen was signed to an undisclosed deal with
Orlado Magic. Allen's final NBA game ever was Game 5 of the 2011 Eastern Conference First Round on April 26, 2011, in a 101–76 win over the Atlanta Hawks. In his final game, Allen recorded 1 point and 1 rebound. Orlando would go on to lose Game 6 and get eliminated from the playoffs 4 - 2. ==Coaching career==