The lure of Olympic gold gave Ben Smith sleepless nights for much of his lead-in to the World Cup.

Unlike four years ago, Smith didn't need to sweat his All Blacks selection but his dilemma over which game he would commit to next year proved a difficult decision.

The Otago product swung between signing on for Gordon Tietjens' sevens squad or sticking with his beloved Highlanders and the XV-man game where he's now renowned.

Smith won gold at the Commonwealth Games in Delhi in 2010, one year after making his Test debut in Italy. He knows what it takes and was an obvious recruit.

In the end,  the added time away from his family was the deal-breaker. Smith joined All Blacks first five-eighth Beauden Barrett by opting out of a shot at Rio.

"It was a tough decision. I had a few nights where I stayed up a wee bit thinking about it," Smith said. "It's a great opportunity to go to the sevens. The way I play rugby I wouldn't like to commit to the Highlanders and not be able to follow it through.

"For me it was weighing up also how much time I'd spend away from my family. I've got a young daughter. It sort of became about them as well as my rugby.

"I wanted to make sure I was at home to help them out and to see her grow up a wee bit. I thought with the sevens you would have to be away quite a bit going around the world. You never know. Things could change if there's some injuries but at this stage I've put that on the backburner.

"You've got to weigh all the positives and negatives with every decision. The one thing I thought the whole way through was they were both good decisions. Both would be great opportunities."

Such considered thinking has been a feature of Smith's on-field rise, too.

His importance is probably best captured by the fact he has gone from being overlooked for the 2011 World Cup, missing out to Zac Guildford, Israel Dagg, Cory Jane, Mils Muliaina and Isaia Toeava, to the only specialist fullback in this year's squad, with Nehe Milner-Skudder, Barrett and Colin Slade providing cover.

Leading the Highlanders to their maiden Super Rugby title could now be capped off by playing a leading role in the All Blacks' quest for their first overseas World Cup success.

"I know what it's like to miss out. I had that a few years ago," he said. "There were a lot of outside backs then and nothing has really changed. It was competitive and I missed the cut at that time so a World Cup is always something I wanted to be part of."

Much has been made of Smith's persona; in particular the suggestion his understated nature prevented him from establishing his class well before now. He certainly doesn't fit the stereotype of the brash rugby player. To be fair, only now is he enjoying regular game-time in his preferred role for the All Blacks. He was never one to complain, but the centre experiment didn't enhance his case.

Highlanders coach Jamie Joseph is well placed to assess the belief his demeanour held him back, having played two Tests between 2009 and 2012.

Joseph describes Smith as not only the best professional he has coached, but the best player at the Highlanders. That's some compliment when you consider the influential presence of All Blacks Aaron Smith, Malakai Fekitoa and Waisake Naholo.

"I guess it's just taken him a bit of time to realise it himself," Joseph said. "He's so humble that it may have affected his chances because that humility off the field can be perceived at times as a lack of confidence. It's not – he's got a lot of confidence in his own abilities. If you don't know him well enough you can get the feeling he may lack some confidence but he certainly doesn't.

"There's nothing really Bender can't do. His best attribute is he doesn't have a seven out of 10  game. It's either nine or 10. He only has one speed; one volume. The beauty is you know what you're going to get every time he puts his boots on.

"Selfishly he's our captain and our best player on field. Off the field he's our best leader so we really rely on him to drive a lot of things. He's a great role model for the younger and older players because he's so consistent. The fact he's not going to the sevens is a real bonus for the Highlanders."

Leadership is not something regularly associated with Smith. Mainly because of his shy public image.

But his influence in transforming the Highlanders can't be understated. Two years ago Joseph's men finished second last in Super Rugby.

Sweeping changes were made, including shifting the captaincy from Jamie MacKintosh to Smith and Nasi Manu.

Smith's leadership style is to listen before speaking. What he says is direct.

"To be able to do that alone is massive but to then be one of the best players at All Black level is quite amazing," Joseph said. "He hasn't proved people wrong but he's improved every year as a rugby player and a genuine leader."