Born to play test matches for a country that barely plays them, the former Tauranga Boys' College batsman probably has even better to come.
He went through the 2000-runs barrier in compiling his century, and has 12 half-centuries to go with his six tons in 57 innings.
He has yet to score 1000 test runs in a calendar year but has a head start this year and opportunities for big runs against Pakistan and Sri Lanka after the West Indies.
If he does, he will average 40 and would have scored about the same number of runs as Mark Richardson, Andrew Jones and Glen Turner.
It seems likely Brendon McCullum or Ross Taylor or both will eclipse Stephen Fleming's New Zealand record of 7172 test runs, and just as likely that Williamson will catch them all.
He has shown an ability to bat for longer periods against the world's best attacks than any of the others, and needs just three more centuries to match Fleming's nine.
With cricket in turmoil it is fantastic to see someone excel in a New Zealand shirt who works so hard at his game.