Walker also grabbed six rebounds and dished off seven assists as the Bobcats finally bested the Mavericks after going 0-16 against them all-time.
Charlotte forced overtime when Ramon Sessions hit a driving layup with 2.8 seconds left in regulation and Byron Mullens (14 rebounds) gave the Bobcats the lead for good with an overtime dunk.
Michael Kidd-Gilchrist added 25 points and 12 boards for Charlotte.
O.J. Mayo led Dallas with 22 points.