On a landmark day for Smith at the SCG, Australia's stand-in captain went past English great Jack Hobbs for the second most Ashes centuries and runs.
The 36-year-old's unbeaten 129 also ensured Australia would hold a 134-run first-innings lead after day three, with the hosts 7-518 following Travis Head's earlier 163.
Smith gave the strongest indication yet on Saturday that he would likely play on into the 2027 Ashes, but if this was to be his last Test against the old foes it would be a fitting farewell.
In a series where he has had limited chances and missed Adelaide through injury, Tuesday showcased Smith at his peak.
Playing on his home ground in Sydney, the cover drive returned with impact and Smith drove back down the ground with precision whenever England's bowlers went too full.
With the field set back for parts of his innings he was the perfect contrast to Head, willing to ride the short balls and knock singles around the SCG.
It was in that fashion his hundred came, tapping a Jacob Bethell half-tracker behind square on the legside for three before raising his arms aloft.
His century still came off 166 balls - the same number that Head faced for his 163 - but it still felt as if Australia's master batter was able to wear England down following their own best innings total of the summer of 384.
Such is Smith's longevity, he has now scored centuries in seven separate Ashes series. Only Sir Donald Bradman has hundreds in eight.
Tuesday's ton was also Smith's 13th against England, going past Hobbs' 12 in Ashes series and again leaving him only behind Bradman.
And in cricket's most fabled series, Smith is also now only second to Bradman (5028) with runs scored, after going past Hobbs' 3636 while in the 80s.
He also now has five centuries at the SCG, second only to Ricky Ponting's six.
"I just love batting here," Smith said on Kayo after play.
"Obviously it's my home deck. I know the ground really well. When I get in I really like batting here. The pace of the wicket suits the way I play."
England did offer one chance to Smith on 12 when Zak Crawley grassed a tough chance at leg slip.
Otherwise his only other concerns were examples typical of the famously fastidious Smith.
He stopped play because of a stray piece of paper on the sightscreen and grew concerned at spectators moving.
At one stage he even asked Brydon Carse to turn his sunglasses around on top of his cap in the field because of the glare, before later signalling wides to bouncers.
Smith may be one of cricket's more unique Ashes characters of this century. But after Tuesday he can now lay claim to officially being the best besides Bradman.
"While he's enjoying it, he's going to hang around and it'd be silly not to say we want him forever," Head said.
"A couple of hundreds last summer perked him back up. And he has spoken about the enjoyment he has in this group."
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