Smith, who opted to bat and named an unchanged XI, steadied in style after David Warner and Usman Khawaja departed in consecutive overs.
Australia slipped to 2-75 late in Thursday's opening session, leaving the game in the balance.
Smith responded with the 16th Test ton of his career, although he was dropped on 53 in the final over before dinner by keeper Sarfraz Ahmed.
Smith also had a bizarre reprieve on 97, when he feathered an edge to Sarfraz but none of the tourists appealed.
That chance came in Pakistan's first over with the second new ball, which was delivered by Mohammad Amir.
Amir was responsible for a couple of costly errors in the field, including one in the 70th over that appeared to result in a serious knee injury.
The left-armer grimaced and was taken to the rooms on a motorised stretcher after digging his knee into the turf while sliding to stop a ball.
Commentators predicted it was a series-ending injury, but Amir returned to field and bowl soon after.Amir regularly challenged Smith in his final spell but couldn't stop the in-form batsman scoring his first ton in a pink-ball Test.
It was also Smith's maiden Test century against Pakistan, leaving Bangladesh and Zimbabwe as the only Test sides yet to be on the receiving end of a Smith hundred.
It was a watchful innings, particularly when the right-hander negotiated the second new ball and spent 28 balls in the nervous nineties.
Renshaw, who finished 34 not out in Adelaide to help deliver Australia victory against South Africa on Test debut, was again watchful but scored freely whenver Pakistan's pacemen drifted onto his pads.
The opener was caught behind off the bowling of Wahab Riaz, who looked the most threatening of the tourists' three left-armers.