Walker's late charge completed a round of 7-under 63 and earned him his second career PGA Tour win with a total of 17-under 263.
His only other triumph came in October at the Frys.com Open.
Overnight leader Chris Kirk claimed sole possession of second place at minus-16 with a round of 4-under 66.
Jerry Kelly, who won the Honolulu event in 2002, registered a 65 to take third at 15-under 265.
Fourth place went to Harris English (67), who finished at 14-under.
Marc Leishman (65) claimed fifth one shot further back.