In reply to South Africa's 8-190 on Sunday at Kingsmead, Head thumped a career-high 91 off 48 balls to help lift Australia to victory with 13 balls to spare.
Josh Inglis (42 off 22 balls) and Marcus Stoinis (37no off 21) joined in on the fun, but it was Head who was the unstoppable force for most of the innings.
Head, whose previous highest score in a T20I was 48no, cracked six sixes and eight fours in his blistering knock.
He was given a life on 55 when Temba Bavuma dropped a tough diving attempt.
Bavuma eventually got his man with a catch in the deep, but Australia only needed five more runs for victory by that stage.
Head had posted scores of just 18 and six in the first two matches, and his display on Sunday is an ominous warning for South Africa ahead of the upcoming five-match ODI series, starting on September 7.
"It's nice to be back and contributing," Head told Fox Cricket.
"There's been limited opportunities in this format for a while.
"I'd been struggling a little bit to find my tempo and how I wanted to go about it at the top.
"I spoke to a few boys, and it was nice to contribute tonight."
Mitch Marsh was named man-of-the-series after plundering 186 runs from 100 balls across his three innings in a stunning start to his reign as captain.
"I'm really proud of a pretty young group coming over here and winning the series 3-0," Marsh said.
"We had a great team effort. We prepared really well, and we took the game on.
"We had a bit of luck at times, but as a team we had the mentality of being really positive."
Australia paceman Sean Abbott was the hero with the ball in game three after snaring career-best figures of 4-31 to restrict South Africa to a total under 200.
South Africa slumped to 2-12 in the third over, but handy knocks from captain Aiden Markram (41 off 23 balls), Reeza Hendricks (42 off 30) and Tristan Stubbs (25 off 16) helped steady the ship.
Donovan Ferreira (48 off 21 balls) then provided the late fireworks after South Africa had slumped to 6-122 on the back of a middle-order slump of 3-6.
Abbott claimed a double-wicket maiden to inspire the middle-order rot, while Stoinis (2-39) did the early damage before being pummelled late.
Spinner Tanveer Sangha, who snared 4-31 on debut in the series opener before being squeezed out for game two, should have had a wicket in his first over on Sunday.
Hendricks was on 18 when he was struck on the midriff by a Sangha delivery.
The ball bounced down and hit the base of leg stump with some force - but the bail didn't budge one bit.
Sangha ended the match with figures of 1-39, while Nathan Ellis (0-50) copped the brunt of South Africa's onslaught, especially when Ferreira was at full force.