Today, at an age when most people of his generation are retired, he's looking in the opposite direction.
MacDonald is co-founder and chair of Day4 Energy, a British Columbia-based solar panel manufacturing company with proprietary technology to offer a booming global market for green energy.
"It's been apparent to me for quite a long time that the world has to evolve to where renewable energy becomes a significant source of our electrical energy and solar, as l like to say, is the king of renewables. It's energy directly from the sun," the 72-year-old MacDonald said in a recent interview at Day4's bustling manufacturing plant in south Burnaby.
A lot of people, particularly Europeans looking for alternatives to fossil fuels, seem to agree.
Day4 commenced manufacturing in 2006 and since then, annual production has quadrupled and is expected to double again within a few months.
This expansion, predicated upon a fundamental reworking of conventional solar technology, is rapid enough to rank Day4 second on The Vancouver Sun's list of the Top 50 fastest-growing companies in B.C.
The B.C. public company's entire 2009 manufacturing output is already sold out, and its patents are already recognized in the United States, the European Union, China, India and Mexico.
The key to its success is a major improvement upon the conventional electrode, or silver wire grid, that sits upon the black background sheet of a solar panel.
Day4's electrode harvests electricity about 20-per-cent more efficiently, in a smaller space, than a conventional solar panel.
In an industry where the manufacturing cost per kilowatt of electricity produced is substantially higher than other types of green power, that's a notable advantage.
MacDonald, an Officer of the Order of Canada, was retired for only a couple of years from his position as chair and CEO of MacDonald Dettwiler, the Vancouver-based satellite imaging and surveillance company, when he had a meeting with prominent Russian physicist Leonid Rubin that convinced him to get back into the business world.
In Moscow for a meeting of the APEC business advisory council, MacDonald was treated by Rubin to a whirlwind look at Russian technological innovation.
MacDonald, himself a rare combination of physicist, engineer, educator and entrepreneur, describes his two-day tour of Russian laboratories and research facilities as "a drink from a technological firehose."
"We were sitting in a coffee shop behind the Bolshoi Theatre," MacDonald recalled in a recent interview at Day4 headquarters in south Burnaby.
"Leonid said to me, 'Of all the things you've seen, which one could we build a business around in Canada?'
"I said, 'It's obvious. Your solar energy project. If you do what you say you can do, and I see absolutely no technical reason why you can't, there's a market.'
"A month later he was in Vancouver. We incorporated the company. This was in May of 2001."
What Rubin did, in essence, was build a better mousetrap.
"This industry has been around for 30-40 years and while they have made huge improvements in the cells themselves, the method of interconnection has not changed in those 30 years. "What Leonid did, is figure out a better way to do it."
Leonid Rubin's son George, already living in Vancouver and a family friend of the MacDonald's, arranged the original meeting of the two men in Moscow.
George Rubin, a physicist who also had business degree, was the "obvious" choice to run the company's day-to-day business, MacDonald said.
By 2002, MacDonald and the Rubins were laying the groundwork for the company.
Leonid Rubin remained in Russia with his technical crew, seeking to turn the electrode prototype into something that could be produced at a commercial level.
"The technical guys were over in Russia and of course the costs were much less than what you could do it for in Canada. When that was done we brought the whole bunch of them over here," MacDonald said.
"They are all here now. Leonid is a landed immigrant along with his wife, and these guys are now the core of the R&D group."
"George and I did the planning and raising the money."
They opened the first manufacturing plant, with total annual capacity of 12 megawatts of solar panels, in the third quarter of 2006.
On July 15, 2008, Day4 announced completion of an expansion that quadrupled manufacturing, from 12 megawatts to 47 megawatts.
They aren't done yet.
The company expects another doubling of production, to 97 megawatts by year's end.
There was more good news. On July 30, Day4 announced successful trials for its next-generation electrode, which is 25 per cent more efficient than its current model.
The company's bottom line is still a work in progress, given the infusions of cash necessary to support expansion.
The company reported a 2.5-per-cent gross profit, $400,000 in second quarter 2008 compared to two per cent or $300,000 in the first quarter and a negative gross margin of 21 per cent for fiscal 2007.
Day4's most recent quarterly report, for June 30, reported total second quarter revenue reached $15 million compared to $13.5 million in the first three months of the year and $3.1 million in second quarter 2007.
The company noted that the 2008 second quarter jump was achieved despite unchanged production capacity, and pointed to an eight-per-cent efficiency gain in its manufacturing process.
In fiscal 2007, Day4's revenue increased 10 times, from $1.9 million in 2006 to $20.9 million last year.
The company hopes to be in the black on a net revenue basis, by the end of this year.
"This is a very scalable process and we can keep expanding it to meet the market," MacDonald said. "Of course these days with all that's going on in the financial world you have to take a deep breath, but the company is in good shape. I'm not worrying about it."