The Dunblane-born songwriter closed his set at Bannockburn Live, the 700th anniversary celebration of the decisive Scottish battle, with Caledonia.
The song is regularly performed at Scottish nationalist rallies but MacLean said it is beloved of both Yes and No supporters, as well as people around the world.
He said: "Bannockburn was such an important part of creating our Scottish identity.
"If we had lost the battle there probably would have been no Scotland so it's very special.
"I finished my set with Caledonia, and to hear the audience singing the chorus and look out to the rotunda with the Bruce monument behind was very special.
"Caledonia is a homesick song I wrote when I was young but it's become part of common culture now, and I think people have taken it to their hearts.
"It's the idea of that sense of belonging that everybody has, not just Scots and it's not just about this referendum. People sing it at weddings and funerals, people from both sides of the Yes and No campaign. People love it and that's a big thrill for me."
Bannockburn Live, a key event in the Homecoming Scotland 2014 calendar, was heading for a complete sell out today, with organisers turning a profit by lunchtime yesterday.
It stands in stark contrast to The Gathering, the centrepiece of Homecoming 2009, which went bankrupt leaving many exhibitors out of pocket.
But it wasn't without its controversy, with Visit Scotland taking the event over from the National Trust for Scotland and cutting it from three days to two when it was announced it would be going head-to-head with Armed Forces Day in Stirling.
Homecoming director Caroline Packman said: "We took over the event from the National Trust for Scotland in January at which time we looked at the landscape in Stirling.
"Armed Forces Day had by that time been announced as the national event, which took place yesterday.
"We took it right back to basics and looked at what we felt were realistic visitor projections and decided that the wisest course of action was to have two days of extended entertainment rather than spread it over three, and that certainly seems to have paid off for us.
"The Gathering was a very different event in terms of scale, budget, target audience, and organiser so it was totally different and to draw parallels is not really relevant.
"We broke even yesterday at about lunchtime so there is certainly no question of their being a financial loss.
"Armed Forces Day certainly hasn't impacted on the visitor experience."
There were also fears that both events would be politicised so close to the forthcoming independence referendum.
However, Bannockburn remained largely a politics free zone with only a handful of revellers wearing Yes t-shirts and badges, and the nationalism was reserved for the battle re-enactments where a smattering of cheers for Edward II were drowned out by applause for Robert the Bruce.
Ms Packman added: "This event, and Homecoming Scotland, is not about politics at all. It's about tourism, attracting people to Scotland to come home and rediscover thier ancestral roots, to encourage people to come here and discover the very best of Scotland.
"No event does that better than Bannockburn Live showcasing our history, culture, ancestral heritage and fantastic food and drink.
"About a tenth of the audience is from overseas, a tenth are from south of the border and the rest are from Scotland."