The New Zealand captain struck his 54th delivery to theextra cover boundary as the packed house rose to acclaim the hero of the moment.
McCullum waved his arms, got a hug from batting partner Corey Anderson as he savoured his 12th test century and second against Australia, going on to reach 145.
He eclipsed the old mark of 56 balls, jointly held by West Indian Viv Richards and Pakistan captain Misbah-ul-Haq.
Image 1 of 9: Brendon McCullum bats during day one of the Test match against Australia at Hagley Oval. Photo / Getty Images
McCullum's innings included 16 fours and four sixes and came against a backdrop of New Zealand being a parlous 32 for three when he came out to a guard of honour from Australia's players and a standing ovation.
He had a huge slice of luck on 39 when caught by Mitchell Marsh, a one-handed screamer at gully off James Pattinson. He'd walked 20 metres away from the wicket when the replays showed it to be a no ball.
From then on, he didn't look back. With Anderson, the pair hammered 55 in one four-over burst and McCullum went to his century with 6, 4, 4, 4 in successive Hazlewood deliveries.
From the time of his reprieve, McCullum hit 11 fours and two sixes, 56 of the next 61 runs to reach his century.
In his only previous test on Hagley Oval, on Boxing Day 2014, McCullum plundered 195 off 134 balls against Sri Lanka.
At tea, New Zealand, on the back of a 179-run stand between McCullum and Corey Anderson, had reached 273 for six off 50 overs, with BJ Watling on six and Tim Southee on five. The session had produced a whopping 199 runs off 24 overs.
Anderson, having completed a fourth test 50, skied offspinner Nathan Lyon to be caught at short cover for 72 off 66 balls.
The pair had toyed with Australia's bowlers who had bossed the first session, after Australia had sent New Zealand in. Josh Hazlewood's first four overs of the second session went for 57, while Marsh was plundered while Pattinson's first six went for 44.
If anything, today's innings only re-emphasised how much McCullum, firing at his best, will be missed after this match.
There were a mix of unorthodox and streaky shots, blended with thunderous drives, audacious pulls and he left Australia grasping in search of a way to stop him.
In the end it took a fine sprawling catch from Lyon at deep square leg to remove McCullum at 145, off 79 balls with 21 fours and six sixes.
McCullum had spoken before the test of wanting to give something back to the people of earthquake-ravaged Christchurch. He did it with bells on today.
Brother Nathan McCullum, in the United Arab Emirates playing in the Pakistan Super League, tweeted: ''Unreal little bro. Amazing!!''
