But disaster struck for the 24-year-old Victorian on the par-three 13th, when he found the water off the tee and recorded a double bogey.
Herbert had a chance to force a playoff, needing to birdie the last hole, but he overshot the green and landed in the water. A bogey saw him card a four-under 69 to finish 19-under for the tournament in outright second place, two shots ahead of compatriot Nick Flanagan, who fired a five-under 66.
Kennedy earns $240,000 for the win, and will improve his world ranking from his current position of 135.
The New Zealand challenge failed to materialise early on the back nine. Both 2017 champion Michael Hendry and Harry Bateman made the turn at two-under, to move to 13-under for the tournament, but they couldn't capitalise on the short par-five 10th, both missing short birdie putts.
Hendry briefly rallied with birdies on 11 and 12 to close to within four of the lead, but that's as close as he got. He pulled his tee shot left on the par-three 13th, landing in thick rough, and couldn't get up and down. The subsequent bogey effectively ended his challenge.
He missed a short birdie putt on the 14th, and although he birdied the par-four 15th after a brilliant approach, he was too far back to challenge the lead, and carded a four-under 67 to finish at 15-under in a tied for fifth, alongside Bateman.
"The whole week the putter didn't really gel with me," Hendry said. "I just thought to myself 'at least give them a chance to go in by getting to the hole'. That was all I tried to do coming in, I hit a lot of good shots, but they just didn't fall my way this week."
The big surprise was young South Korean Joohyung Kim, who led outright for the first two rounds and was tied with Herbert heading into the final day. He struggled to get going and back-to-back bogeys on the fifth and sixth holes ended his challenge, as he quickly fell four shots behind playing partner Herbert.
He dropped another shot on the 10th and settled for a one-under par 70 to finish outright fourth on 16-under.
Kieran Muir was the third Kiwi to finish in the top 10, shooting a three-under 68 to finish at 13-under in a tie for ninth. Young Kiwi pro Nick Voke saved his best for last, carding a six-under par 65 to finish 10-under for the tournament in a tie for 14th.
