The Englishman went into the final round with a two-shot lead and rarely looked like opening the door for the chasing pack on Sunday, treating the crowds to a ball-striking masterclass as he made an eagle and six birdies in a flawless 63 to finish the tournament on 30 under par.
Smith's wire-to-wire victory caps a superb 2022 season and sees him move into the top ten on the DP World Tour Rankings in Partnership with Rolex and return to the winner's circle for the first time since the 2017 Porsche European Open.
His winning total is one better than the DP World Tour record, set by Ernie Els at the 2003 Johnnie Walker Classic, but due to preferred lies this week Smith's tally does not go into the record books.
Gavin Green finished alone in second after closing with a brilliant 64 to finish on 27 under par.
Green barely put a foot wrong all day, impressing with some magnificent shots as he attempted to reel in Smith but in the end the Englishman proved impossible to catch.
Tapio Pulkkanen was five shots further back in third, one ahead of fourth-placed Eddie Pepperell.
German duo Hurly Long and Sebastian Heisele were tied for fifth on 19 under, with Heisele heading into retirement on a high.
Everyone who came into this event in the top 117 on the DP World Tour Rankings managed to stay there to secure their cards for next season, with Sebastian Garcia Rodriguez claiming the last spot despite missing the cut this week.
Renato Paratore came agonisingly close to reaching the right side of the line but finished in 118th spot despite a stunning 58-foot birdie on the last.
After an uneventful start, Smith made his first birdie of the day from seven feet to prevent Green from joining him at the summit.
Smith then sent his approach at the par-five fifth to 27 feet before rolling in the eagle putt to re-establish the two-shot advantage he began the day with.
He gave himself good birdie chances at the seventh and eighth but was unable to take them, before picking up a shot at the ninth to head to the turn in 31.
Smith made it back-to-back birdies from ten feet at the tenth but gave a glimmer of hope to Green when he got into tree trouble off the 11th tee and had to take a drop.
However, he played a stunning recovery shot to somehow escape from there with a par and avoid any damage to his lead.
Smith had an outside chance of getting to 29 under at the 12th but his 56-foot eagle putt pulled up just short and he had to settle for a birdie there.
A birdie for Green at the short 13th reduced Smith's lead to three shots but the Malaysian bogeyed the 14th after finding the water, restoring Smith's four-stroke advantage.
Smith kept his foot on the gas, converting his 15-foot birdie putt at the 15th to move five clear with three holes to play.
He tapped in for a birdie on the 17th after narrowly missing his eagle try before safely parring the last.
“Over the moon”
Smith said: "It’s just amazing. It’s been a long grind for those five seasons, just pushing it out and finally getting over the line today. Over the moon.
"I knew that today and every day I’d have to get off to fast starts and make sure I made lots of birdies.
"I knew there would be a lot of good scores out there and guys trying to catch me. Gavin was trying to get there and he was getting closer and closer but I managed to hold him off.
"It was a little bit (like match play). When we got down the last five or six holes, it got to that sort of stage. I knew he was four shots ahead of the guy in third so it was just between us two.
"It’s nice getting the first win but then it’s great knowing you can do it again. It’s more down to the pressure I put on myself to get the win and now I’ve got my second one we can push on for a couple more."