The Black Caps were in huge trouble when captain McCullum strode to the crease in the second innings at 3-52 on Day 3 and still requiring a further 194 runs just to make India bat again after the tourists took a 246-run lead on the first innings of the Second Test in Wellington.
It looked a mere formality that India would cruise to the victory and level the two-Test series, but McCullum had other ideas and then he found a partner in crime in wicket-keeper batsman BJ Watling at 5-94 to put on one of the most incredible performances in Test cricket history.
In the end, McCullum and Watling safely guided New Zealand to stumps on Day 3 at 5-252 with an overall lead of just six runs.
That was a terrific effort, but what happened on Sunday was simply amazing as McCullum and Watling batted almost the entire day together ending up compiling a 352-run partnership before Watling's knock came to an end on 124 late on the fourth day.
New Zealand at that stage were only 200 runs in front so India was still right in the contest, but McCullum kept going and found another willing partner in the form of debutant all-rounder Jimmy Neesham.
McCullum and Neesham survived through to stumps on Day 4 with the score 6-571 with an overall lead of 325 with the skipper not out on 281 within sight of New Zealand's first ever triple-century while Neesham had done well in support moving to 67 not out.
India's bowlers had their spirits driven into the ground having already bowled 189 overs in the second innings so they weren’t up for the fight on the morning of Day 5, but a big Wellington crowd turned out to see McCullum create history.
And the 32-year-old didn’t disappoint with the captain moving past Martin Crowe's previous New Zealand best of 299 to make 300 and eventually be out for 302 when caught behind off Zaheer Khan by MS Dhoni.
The damage to India had been done, though, and history had been made in McCullum's remarkable knock.
When he was out, New Zealand's score was 7-625 with a lead of 379 with Neesham also reaching a terrific century in his first Test appearance for the Black Caps.
In the end, New Zealand declared on 8-680 with Neesham remaining not out on 137 from just 154 balls with 20 boundaries.
That gave New Zealand an unassailable lead of 434 so the series victory was secured and with just over one and-a-half sessions remaining to see if the Black Caps could pull off what could well have been the most amazing Test win ever.
India's bowlers underwent an incredible workload with Zaheer Khan finishing with 5-170 (51 overs), Mohammad Shami 2-149 (43), Ravindra Jadeja 1-115 (52) and Ishant Sharma 0-164 (45).
India started disastrously crumbling to 3-54 with Murali Vijay making seven, Shikhar Dhawan two and Cheteshwar Pujara 17, but the tourists didn’t lose another wicket.
Virat Kohli ended up 105 not out and Rohit Sharma 31 but it didn’t stop India from losing the series to New Zealand.
Along the way to coming back from the 246-run first innings deficit to secure the draw and series win, New Zealand and McCullum set a long list of records all-time and for their country.
McCullum is now the only New Zealand player to ever reach 300 surpassing Crowe's 299 he made against Sri Lanka in 1991 also in Wellington.
McCullum was at the crease for 774 minutes, 12 hours and 54 minutes, in the longest Test innings ever by a New Zealand player and the eighth longest all-time overall.
However, it was far from a one-off knock from McCullum.
He scored 224 against India in the First Test to hep New Zealand to a 40-run victory as he became just the third batsman ever behind Don Bradman and Wally Hammond to score a double and triple-century in consecutive Test matches.
Along the way, McCullum surpassed 5000 Test runs for his career to now have scored nine centuries and average over 38 in his 84 matches for New Zealand.
McCullum couldn’t have created history without strong support, though, and that's exactly what he got from Watling (124) and Neesham (137 not out).
McCullum and Watling combined for a 352-run sixth wicket partnership in 678 balls.
Their partnership is the highest for the sixth wicket in Test cricket history and is New Zealand's third highest partnership for any wicket ever.
Neesham's 137 not out was the highest score ever by a No. 8 batsman on debut in Test history as he became the 10th New Zealand player to score a century in his first match for his country in white clothing.
Remarkably, Neesham only played at the Basin Reserve because in-form top-order veteran Ross Taylor was forced to withdraw to be present for the impending birth of his child.
Taylor has been in remarkable form this summer scoring 674 runs in Test cricket against Bangladesh, the West Indies and India at an average of over 112 with an unbeaten 217 and two other triple-figure scores.
So as well as Neesham did, it's unlikely that India would have been any better off had Taylor still kept his place in the side.
New Zealand's final total of 8-680 is the highest score in Test history in the second innings of a match and it's also the highest ever Test score by the Black Caps in either innings.
In both aspects, it surpasses New Zealand's 4-671 scored against Sri Lanka in 1991.
Meanwhile, by winning the series it is the first time that New Zealand has done so at home or away against India since 2003.