Leishman, who joins Rod Pampling and Jason Day as Australian winners of the event, began the final day three shots off the pace of Kisner and Hoffman and, although an early bogey put the Victorian even further behind, he steadied the ship with birdies at the 4th, 6th and 10th to be on the heels of the leaders.
The 33-year-old catapulted himself into the lead when he holed a 50-foot eagle putt at the par-five 16th and although he missed the fairway and green at the last, he produced a delightful bump-and-run from just short of the green to set up an all-important par save to hold Kisner and Hoffman at bay.
Leishman's win secured him a cheque for US$1, 566,000, will move him very close to the top 30 in the world rankings and assures him a start at next month's US Masters having been outside the required qualifying criteria prior to the victory.
MARC LEISHMAN'S WINNING PUTT AT BAY HILL
“I’ve been playing well all year,” said Leishman. “I put the new Callaway driver in at the start of the year and it really has been a game changer. This game is certainly easier out of the fairway.
“The putter has been amazing this year also, especially this week, but all year it has been close and haven’t quite played how I have wanted to on Sundays.
“I have had quite a few chances to win this year. Going into Sundays, I've been two, three, four back basically every tournament. So, it is disappointing to do that, but you really learn stuff when you don't, when the outcome's not what you wanted it. And I felt like I learned a lot from those earlier in the year. I've been playing well, it's just a matter of putting four rounds together.
“The more you get your self into that situation, the better you get and luckily those experiences from earlier this year paid off and I was able to make the putts when I needed to and walk away with this [trophy]. It's very nice.
“And like you said, the Masters is another, it was certainly a goal of mine to, I knew that the cut off was after the Match Play and I only had two events left, so I need to get it done or sit at home and watch the Masters, which is not fun if you've already been there and played there, because you know how cool it is to be there."
The significance and importance of his win in an Arnold Palmer-inspired event was not lost on Leishman but it was also important for personal reasons as well.
“This is a special week. Mr Palmer was an awesome guy who I have been lucky enough to meet on several occasions at this tournament so to honour him has been huge. This is also the first time I have won a tournament with my family here so to have Audrey and the boys and my caddy Matty has had his family here also so it has been an awesome week.”
The illness to Leishman's wife Audrey two years ago has been well documented and the toxic shock syndrome that so nearly took her life has altered Leishman's perspective on life.
“It's been a wild ride and you certainly do appreciate the good times a lot more and appreciate just everything, your kids and your family and just having people around. It's just great to be able to share this with someone. If it was just me, it wouldn't be anywhere near as fun, if they weren't with me.
“If Audrey had have passed away, I was going to be a dad and that was it. There was no other sort of, it didn't cross my mind to keep playing golf. So, that first six months, just every time I was on the golf course, I was just so happy to be on a golf course and be healthy and all that.
“Obviously, your perspective doesn't stay like that for a long period of time, I feel like I've still got a very good perspective, but yeah, it's, it can be life, it's life changing. Something like that.”
Rounding out the top-5 at the Arnold Palmer Invitational were Rory McIlroy and England's Tyrell Hatton who each shared 4th while Greg Chalmers was the next best of the Australians in a tie for 17th.
Defending champion Jason Day finished 23rd, Cameron Smith 34th, Aaron Baddeley 41st and Ryan Ruffels 56th.
MARC LEISHMAN ON FAMILY LIFE & GOLF