He later signed with Union Olimpija of Slovenia′s Premier A Slovenian Basketball League for the 2008–09 season. However, he left the club in November 2008 and signed with EWE Baskets Oldenburg of Germany in February 2009 for the rest of the season. In November 2009, the Rio Grande Valley Vipers selected Wallace in the second round of the 2009 NBA Developmental League (D-League) draft. In July 2010, he joined the NBA D-League Select Team for the 2010 NBA Summer League. Wallace later signed with FC Bayern Munich of Germany, where he spent two seasons. On July 28, 2012, he signed with Belfius Mons-Hainaut of Belgium for the 2012–13 season. On July 8, 2013, he signed a one-year deal with the Walter Tigers Tübingen in Germany. On May 23, 2014, he signed a one-year contract extension with Tübingen. On June 30, 2015, Wallace joined the Charlotte Hornets for the 2015 NBA Summer League. From 2015 to 2016, he played for Recreativo do Libolo of Angola. In August 2016, Georgetown University announced that it had hired Wallace to return to the school's basketball program as a special assistant to coach John Thompson III.