He had help from Corey Anderson, Tim Southee and Ish Sodhi. But the operation turned on the leader.
McCullum is in elite batting company for New Zealand. Only six batsmen have made more in a test innings, excluding his own 225 four years ago, also against the Indians.
Among the best ways to lead a group, or team, is by the strength of your personal performance.
So, a couple of numbers. Consider McCullum's overall batting average in his 83rd test - 36.62. Now as a captain batting in New Zealand? 80.37 from nine innings.
Is that just by chance, or is there something more to it? After all, he's had batting failures overseas as captain. It may be that doing the job before the team's supporters brings out something extra in him.
Williamson described McCullum's batting on Thursday, from the time he completed his first 100 through to stumps, as ruthless.
Yesterday he kept up that attitude. So, while there were bold strokes - no McCullum innings will ever be without a quota of them - he also bided his time, if that was what the mood of the moment demanded.
For more than seven and a half hours, McCullum denied the Indian attack. His stickability was an important statement of intent.
He badly wants this team - his team - to win, and retain, respect. McCullum did his bit in spades over the past two days.