The 34-year-old from Warrnambool secured his fourth United States PGA Tour title with a superb exhibition of ball-striking and putting in the $US7 million CIMB Classic at TPC Kuala Lumpur.
He made four consecutive birdies starting at the second hole in the final round before picking up shots at nine and 10.
Leishman becomes the first non-American to win the tournament since its inception in 2010 and earns him a $1 260 000 paycheque.
He also receives invitations to the 2019 Sentry Tournament of Champions, a winners-only event in January, along with two major championships (Masters Tournament and PGA Championship) and THE PLAYERS Championship.
Leishman's wife Audrey was diagnosed with acute respiratory distress syndrome and toxic shock syndrome and she almost died.
"It was a very tough time that we went through, but it certainly made us stronger as people, made us appreciate just the everyday things, our kids more, friends, family, everything", Leishman said of his wife's illness. "That was the longest putt I made". His only miscue on the day was a bogey on No. 13, but he was well ahead by then.
"Sure, it was disappointing to finish T-10 after being in lead, but I would gave gladly taken this before the start, coming from where I was before this week". "Kind of got a little loose there a little bit on the back nine, maybe ran out of gas a little, but it was nice to finish up with a birdie and get some momentum going into tomorrow", Woodland said.
"Delighted like you wouldn't believe". I made four birdies in a row and I was really happy with the way I was playing and I knew I had a chance as I was only three behind.
The US' 2009 Open Championship champion Stewart Cink shot the lowest round of the day, a nine-under-par 63, to move to tied seventh place at 15 under par along with five others, while his compatriot Austin Cook (68) was the lone man in sixth place at 200.
The PGA Tour will remain in Asia the next two weeks for the CJ Cup in South Korea and the World Golf Championships-HSBC Champions in Shanghai.