Terms of the deal were not disclosed, but the Dallas Morning News said it was a multi-year deal with only the first season guaranteed, and with both Christie and the Mavericks holding options.
Christie was waived by Orlando last week as part of the NBA's luxury-tax amnesty term.
Christie, 35, who is known more for his defensive prowess, was dealt from Sacramento to the Magic for Cuttino Mobley and Michael Bradley in January. He averaged 6.6 points, 3.8 assists and 3.4 rebounds per contest and is a natural swingman who can also play the point.
For his career, Christie has averaged 11.4 points, 3.7 assists and 4.1 rebounds per contest while playing for the Lakers, Knicks, Toronto, Sacramento and the Magic. He has been named to the NBA's All-Defensive Team four times.
Dallas also signed seven-foot free agent center DeSagana Diop. In four years, Diop has averaged less than one point and 2.6 rebounds over 193 games.