Only he always had a stammer, so he never expected the idea to escape the lands of fantasy and enter the real world. When it did, nobody was more surprised than he was.
He was also even more unprepared than most of those who have leadership thrust upon them. Luckily, he says, there was no shortage of helpful advice around — John Smit, then his club colleague at Saracens had captained a World Cup-winning South African side; Steve Borthwick, a former England captain, is still there and still someone to bounce ideas off. And then there were some all-time greats of Scottish captaincy.
"I made a lot of phone calls, I spoke to lots of guys," Brown said. "I spoke to Jason White, PC [Peter] Brown, Jim Telfer and all these sorts of guys. You just ask them what they think and what they experienced. It's great to speak to them because you pick up little bits of knowledge that you can use.
"It's pretty intense. It took me back to being a schoolboy, just sitting there when Jim [Telfer] was talking to me. Obviously he's a Melrose man, someone I've looked up to all of my life, and I massively respect what he's got to say.
"It [captaincy] is very special. It's the sort of thing that as a child I always thought would be great, but I never thought I'd get to do it because of the stammer and all that sort of stuff. To actually do it is almost more than a childhood dream."
Two years down the line and preparing to take on Ireland in Dublin at the weekend, Brown looks and feels more settled in his role. He has had both the time and experience to crystallise all that, often conflicting, advice, into his personal style, and his confidence is blooming.
"Ultimately you've got to lead as yourself. You can't say, 'Okay, I'm going to be exactly like him or him'. That's what I try and do, but I also try and take the best bits from each of these characters," he said.
"I think the best advice has got to be: you've got to play well. Players want to follow a leader who is playing well and doing the dirty work, who is not asking them to do things he wouldn't do himself. That's the foundation. Then there are all the layers on top of that."
It matters. In Paul O'Connell, Ireland have a captain who exemplifies that style of leadership, somebody who is relentless in his personal standards. If Scotland are to have the slightest hope of defeating his team on Sunday, they have to match or better the passion that their captain instils and the rest follow.
"He's an iconic figure in world rugby. He's been on three or four Lions tours. He's obviously a very good player, but I think he's a also a talisman for the Irish side and I'm sure he'll have them well fired up on Sunday," Brown says before insisting that his team are also in a good place. "What's exciting now is the blend we've got; we've got some older guys in the squad, but there's a lot of young guys coming through. That's really exciting. If you look at our backline now, there's a lot of guys there who have got a massive cutting edge. So we need to make sure we give them the ball in a bit of space."
That said, the real key to starting the Championship with Scotland's first win since 2006 is to try to find that elusive consistency. In almost every match since Scott Johnson took charge they have had spells where they have demonstrated enough ability to win the game without being able to sustain them long enough to claim the result.
"It's important we play well, that's the thing that we are focusing on," Brown said. "When we get it right, we are a very good side, but it's about making sure we get it right more often. If we do that, we can put any side under pressure."