The Briton had led the Race to Dubai heading into the season-ending DP World Tour Championships at the Jumeirah Golf Estates, but for much of the final day's play it looked as though his compatriot Justin Rose would take the $1.25 million bonus awarded to the golfer who finishes top of the money list.
Rose arrived in Dubai trailing Fleetwood by 256,737 points, but was in superb form after winning back-to-back European Tour titles in China and Turkey.
The 2013 US Open champion looked on course to snatch the hefty cash bonus after entering the final round at the Earth Course with a one-shot lead and with Fleetwood two shots off the pace.
Rose started the final 18 holes in composed fashion, picking up four shots on the opening nine holes, before his good work unraveled with three dropped shots in five holes at the 12th, 14th and 16th holes. The setback saw the Briton cede his tournament lead and his advantage over Fleetwood.
After scrambling a par at the 17th, Rose was left needing a three at the par 5 18th but had to settle for a birdie after his monster eagle putt failed to drop.
His stuttering close saw Rose slip into a tie for fourth, two shots behind eventual winner Jon Rahm of Spain who finished on 19-under par.
Rahm's second European victory of the year earned the 23-year-old $1.4 million and was a fitting end to his season after being crowned Europe's Rookie of the Year
earlier in the week.
Fleetwood had an unspectacular final round, closing with a two-over par 74 and tied for 21st place, but it was enough to seal his maiden Race to Dubai title.
Despite wilting in the closing stages, Rose was gracious in defeat, tweeting: "Wasn't my day... Hats off to Tommy Fleetwood on a great year ..."
The 2017 season has been far and away Fleetwood's best year -- his previous highest year-end placing was 19th back in 2014.
After two European Tour victories as well as a fourth-placed finished at the US Open in June, the 26-year-old from Southport is now setting his sights on making a bigger impact on the global stage.
"My ultimate goal in life is to be the best player in the world," Fleetwood said, EuropeanTour.com reported
"That will always be the same. Whether I achieve it or not is another thing but I'll always strive for that.
"I think this year has been a big year in terms of my career. Some of the performances, I have put myself on the world stage a bit more. When we sit down after this year we'll make sure that the goals get high and lofty and that I push myself to achieve more."