As we enter through David Martin's navy blue door in Eaglesham, the silky chords of Bill Evans are wafting into the hall from a CD player in the living room.

The album is Interplay, a reassuring omen for our interview. Moving with an easy agility that confounds his 89 years, Martin shows photographer Colin Mearns and myself into the room crammed with paintings stacked – sometimes 12 deep – against the walls, which are waiting to be uplifted for forthcoming exhibitions. We are not talking retrospectives here but shows of present work and others for paintings soon to be completed. “Ninety next year,” he says. “I can’t believe it, but I suppose the secret is to keep doing things. People who retire and just sit and watch television, well, they seem to fade away.”

Martin belongs to that impressive vintage of painters attached to Glasgow School of Art in the 1940s. It included the exuberant David Donaldson who had been teaching there since 1938, and Joan Eardley, a fellow student already developing the poignantly atmospheric and figurative work which would bring her distinction. “I seem to remember that she was a year above me. She was a very reticent girl but powerfully observant and her paintings and drawings of Glasgow street children are marvellous examples of sentiment without sentimentality.”

But for his part Martin, always a free spirit, found inspiration in the work emerging from Edinburgh at this time. “Although I enjoyed and benefited greatly from my time at GSA, I wanted to break away from the academic approach to painting that was at the core of my training there. My interests were with the likes of William Gillies and Robin Philipson whose work, to me, was very exciting.” Anne Redpath, whom Martin also knew, belonged in that Edinburgh circle; a much more outgoing character than Eardley “who was so very quiet you would hardly know she was there”.

Eclectic in its influences, Martin’s work has focused mainly on landscape and still life. “I’ve always liked the structure in paintings by Cezanne, and, pretty much from the start, I was into Bonnard, then Braque and Picasso. And also I was very keen on Graham Sutherland when he was on the go.” Some of Martin’s new paintings – currently on show at the Roger Billcliffe Gallery in Glasgow, and others destined for the Richmond Hill Gallery in London from August 30 – still evoke such masters. “Something from all of these sources has rubbed off on me but I hope my art has been moving all the time. I know some artists, whom I won’t name, who’ve been doing the same thing for 40 years.”

Landscapes have always been a notable part of Martin’s creativity. “In the early days I went out laden like a pack mule with canvas, easel, paints and brushes. But that didn’t last very long because I much preferred working in the studio from drawings done on site, and going beyond the visual to interpret the subjects that interest me.”

Martin was born in Glasgow and it was at GSA that he met his late wife, the painter Isobel Smith. But before that his student days were interrupted by four years in the RAF, from 1942, when he became an instrument mechanic servicing aircraft mostly in southern India.

By that time Martin was regarded at GSA as a mean hand at jazz piano, his band, the David Martin Quintet were a hot ticket for student dances. “From my teens I’d been listening to people on the radio like George Shearing. Then when I was in the RAF and stationed at Bath, a band called the Harry Parry Rhythm Sextet came to play at the town hall. I asked if I could have a weekend pass to see them but the answer was no. So, I went awol and you’ve no idea the thrill of fear and adventure you get when you do that sort of thing.”

Did he get caught? “No. When the concert was over I went to the Naafi for a cup of tea, and a couple of military police came into the canteen when I was there. But I managed to avoid them and I got back to the camp without anybody having noticed I’d been missing.” Out of uniform by 1946, Martin resumed the remaining two years of his studies at GSA. “Most of the same tutors were there, including David Donaldson, who would come in, pick up your brushes and get going on your painting, but you wouldn’t mind because you were always learning what real painting was about.” Donaldson had a reputation for flamboyance and Martin remembers him turning up at the art school Christmas ball wearing nothing but a fig leaf and two devil’s horns. “An extrovert wee man, perfectly formed. He did nude portraits of himself with a rose in the appropriate place. But that was him, a nice man but a bit brash. ”

The much respected Hugh Crawford was another key tutor for Martin, one who constantly challenged his students’ powers of observation. “You’d be doing a portrait and he’d study the canvas, then the sitter and say, ‘Look at the speed of the eye.’ He wanted you to catch even the slightest movement; to miss nothing. Some people found him difficult to understand, but I got what he was at straight away.” Even so, Martin turned his easel against portraiture.

“I did a few portraits of friends and my wife, but I wasn’t drawn to commercial portraiture because I didn’t want the hassle of the sitter’s relatives, or the sitter themself, looking at the result and telling me that they didn’t like the nose or the line of the jaw.” He was never tempted, then, to venture into the disjointed portraiture of Picasso? “No, although I am a great admirer because of the quality and invention of the work he produced to a ripe old age. There’s a story that years ago when a Picasso exhibition was on at Kelvingrove, a guy ran from the gallery, shouting: ‘Let me out. I’m beginning to like it.’”

Martin and Isobel moved into The Old Schoolhouse at Eaglesham in the 1950s. She died in 2000 after suffering from Alzheimer’s for 10 years. Upstairs in the drawing room there is an elegant, wistful portrait of her by Martin, painted at the time of their engagement. Otherwise the paintings on the walls are by friends. “I rarely hang my own.” On the staircase, away from the creative chaos of his studio, there is a tiny, signed caricature by Marc Chagall whom Martin met in 1986 when the Russian artist was receiving an honorary doctorate from Edinburgh University. “As he didn’t speak English, we didn’t get very far, but he liked my rosy cheeks and pinched them gently. So, I can truly say I’ve been touched by Chagall.”

From Glasgow to Truro, from London to Osaka, Martin has his devotees. His most avid collector is a Japanese businessman who, in recent years, has bought 109 David Martins, half a dozen at a time. “If I don’t paint, I’m bad tempered,” he says. But that’s not quite correct. If he’s not painting, Martin may well be sitting at his Bechstein, as he was at the end of this interview, restless fingers conjuring haunting blues from nowhere.

David Martin at the Roger Billcliffe Gallery, Glasgow, until June 28, and at the Richmond Hill Gallery, Richmond, London, from August 30 to September 18.