He appears to be thriving as a batsman with the extra weight of leadership.
His test average as captain is 59.54 against an overall figure of 51.16, and that dips slightly in the 48 games in which he was not captain, 49.23.
In 37 ODIs as skipper, Williamson is averaging 47.29, vs 45.9 when not in charge.
National coach Mike Hesson believes Williamson has grown in the job since Christmas. Williamson was reluctant to put a specific time frame on it.
"I don't know if there's a point in time. It's a gradual thing, you're always learning and trying to improve," he said.
"I don't know if it's my stamp as much as it is trying to judge the group we have and move in the best direction you can. It's more about the people in the team than me."
He sees no relevance in his improving batting numbers since being elevated to the captaincy permanently.
"I didn't really know that was the case. There's a million different stats out there. In terms of my batting and contributions to the team, my focus is the same."
Williamson calls it a period of transition for the team since taking over from McCullum.
"When you take Brendon out of the fold, things are going to be different.
"We've had good results, a number of different learning curves, good days and bad days. But ultimately I felt the team are moving in the right direction."
Williamson is now far more involved in all aspects of the team. He identified the off-field bits of the job as most interesting.
"The most enjoyable part is watching the team grow, and hopefully track in the right direction.
"You're learning every day. It's so important you're always dealing with the person. The sport is what you play but dealings with the person are much more important and showing that compassion, and sometimes we do get a bit caught up in results and wanting to win, wanting things to be perfect.
"But when you try and put time into the person, that's something you become a little more aware of when you're in this role."
Williamson acknowledged players need to be handled differently. One approach does not fit all players.
A favourite memory of the season? Williamson plumps for the last test against South Africa, when an under strength side performed admirably and stood one good day away from a series-levelling win against formidable opposition.
"It was a great example of a team get really tight and showing that fight together. The guys came in, picked up their role and ran with it, applied pressure on one of the top test teams in the world.
"The T20 was pretty exciting on those really challenging surfaces, and with guys going over with an open mind and adapting as well as they did."
So, as a first year report card how does Williamson see his team?
"I look at it as a year of growth.
"Guys are wanting to move into leadership roles, which I think is a really positive thing for the side.
"Players who have been there five, six, seven years and have so much to offer.
"We're trying to make something a little more sustainable because we want to be producing the right results more often, more consistently and trying to maintain that culture."
