He started his professional playing career - as a fiddler with the Tannahill Weavers - when he was 20 years old and can look back on 40 years of making his living doing that, writing songs, playing guitar and singing.
Arithmeticians will have deduced this is his 60th birthday year. If the man who wrote Caledonia hadn't been asked to play at the Bannockburn celebrations next month, there would have been something far wrong.
However, that gig - on Saturday June 28 - is far from the grandest on MacLean's current schedule. On Sunday he closes the Perth Festival of the Arts with the premiere of his Perthshire Cantata, an expansion and development of the Perth Amber suite. He gave the same title to his own festival, which happens in and around Pitlochry and Dunkeld in the autumn, when the leaves on the trees famously give the area its most colourful season.
A week after the Perth Festival concert he is performing with the Royal Scottish National Orchestra, launching an album of orchestral recordings of his favourite and best-known songs made with conductor and arranger John Logan for Glasgow's Linn Record label. In Logan, MacLean would appear to have found the perfect partner to take his songwriting and display it on an orchestral platform.
It is probably fair to say that the 20-year-old MacLean would have been astonished at this turn of events, as surprised as he would be that the MacLean family home (and studio) is the school and schoolhouse both he and his father attended in Butterstone near Dunkeld. The songwriter has travelled the world, but he could hardly be accused of straying far from his roots.
The prospect of travel with the Weavers was what made the 20-year-old take the first step. The band was about to leave for dates in Germany but had lost their fiddle player when he was approached to join at the Kinross folk festival. At the time MacLean was working as a gardener in Aberdeen's Duthie Park, following stints tractor driving, laying an oil pipeline, as a milkman and as a Heraldic artist. He resigned and set off on the road, learning the craft of performing from folk singers he refers to admiringly as "the old entertainers".
"The young players are all virtuosos now, but they don't know so much about performing and relating to the public. With those guys it wasn't too cerebral. They could be chatting for 25 minutes and never sing a song. Acoustic music has to have that interaction."
The young MacLean was writing songs in his time with the Weavers but he wasn't allowed to sing them. "You can't do that and be the fiddle player, I was told, and fundamentally I love to sing. I play guitar to accompany myself, and I mistrust the fashion for not being able to play well, but I love the thing of singing."
When he left the group for a solo career, MacLean found an additional eager audience on the other side of the Atlantic for his mix of original and traditional songs, including farming songs from his home area.
"The US is geared up for contemporary songs. People expect to hear songs they have never heard before and I found a whole layer of people doing the same thing as me - that whole troubadour tradition.
"I got guest slots on tours, including with Kathy Mattea, who had just won a Grammy, and I realised it didn't make a lot of difference where you were on the bill as long as you were reaching the people. Ambition can eat you up, and mine's quite small really."
Although it involves a symphony orchestra, the new album with the RSNO does not contradict that ethos. MacLean's partnership with composer and arranger John Logan began when he was a guest on the annual St Andrew's Day concert the orchestra plays with Phil Cunningham and Aly Bain, which Logan, a former sub-principle horn player with the orchestra and now Head of Brass at the Royal Conservatoire of Scotland, has conducted for the past seven years.
Logan says: "We got round the piano afterwards and Dougie said he was interested in working with bigger forces and orchestrations, and then we talked about making a recording, We've got a bit of a system going. He'll come up with a counter-melody or an instrumental line, and he has a tremendous ear, but no notation. He always has an idea of where the music should be going."
If Logan is sympatico, it is partly because he started life as a piano accordion player, and has filled that role in the company of the City of Birmingham Symphony Orchestra (where he played horn for five years before his 17 with the RSNO) and one Luciano Pavarotti. "There's always a gig for an accordionist who can follow a conductor," he jokes.
He likes having other things going on besides playing the horn, and was always involved in the orchestra's education work before conducting engagements and project-based work came up. "I'd meet the artists, do the chart and then conduct, and I found I enjoyed being in charge from the grassroots up."
Working with musicians who do not read music has become a key component of that work, including a concert at Paisley Abbey that combined the RSNO with bands Admiral Fallow and The Twilight Sad; the Burns celebration at the SSE Hydro during Celtic Connections this year; and the recent Gerry Rafferty tribute concert where Emma Pollok, Roddy Hart and Barbara Dickson worked with players from the orchestra.
The songs Logan has orchestrated for the new Linn album cover the gamut of the 200 MacLean has written over the past 30 years or so, its title track being 2003's Til Tomorrow and other highlights including 1986's This Love Will Carry, 2001's Talking With My Father and versions of Ca' the Yowes and Green Grow the Rashes O. Of course there is room for a "nice wee arrangement" of Caledonia, his most covered and recorded song, and one that has long since outgrown its use in a beer commercial.
"Back then it was a song about homesickness, and I was genuinely homesick when I wrote it. I was quite prepared to say no to a beer ad, but the ad was as much for Scottish self-confidence. I'm not a member of the SNP - I want to be able to sing for everyone - but I am a long-standing supporter of independence."
Before the music on the new album is premiered at Glasgow Royal Concert Hall, Sunday sees another Logan/MacLean collaboration, with six entirely new MacLean compositions interleaved with the four movements of the Perthshire Amber suite he wrote with cellist Kevin McCrae for the 1999 Perth Festival to form the Perthshire Cantata that wraps up this year's festival.
Piper Ross Ainslie and fiddler Jenna Reid will be among the group onstage alongside a string ensemble, and the MacLean/Logan creative partnership was still shaping the evening when we spoke. What will be included, however, is some between-song story-telling, just as the old guys taught the Perthshire songsmith 40-odd years back.
Dougie MacLean's Perthshire Cantata has its world premiere at Perth Concert Hall on Sunday. An Evening with Dougie MacLean and the RSNO is at Glasgow Royal Concert Hall on June 7. The 2014 Perthshire Amber festival runs from October 24 to November 2.