An "early claim to fame", he says, was the company's successful sponsorship of Chelsea Football Club for four years - despite being a West Ham fan. He became chief executive of the whole Belron group in 2000.
Under his leadership, Belron has trebled in size, employing 25,000 people and operational in 33 countries. Last year, it achieved €2.8 billion worth of sales (£2.5 billion), up 16 per cent on 2009. It buys eight million pieces of vehicle glass a year - only Toyota buys more windscreens. The company has fixed around 200 million pieces of glass.
But statistics are not everything to the unassuming Mr Lubner, who rarely gives interviews. He places great emphasis on customer service. "It's really important to us - as are our people - making sure they are well-trained, engaged and have all the equipment necessary to deliver a great service."
And of course, extreme weather conditions also help. "We love very cold weather or very hot weather. People are driving round with small chips in their windscreens all the time. When it gets cold, ice gets in, expands and cracks, or when it's hot, the air conditioning is turned on and the difference in temperature causes a crack."
Besides, surely Belron does not suffer in downturns in the same way other companies do? "We are not a cyclical business but we are not recession proof either. In the boom time, things don't really get much better for us." There are also oil prices to consider. "Prices going up means that people will drive less and people driving less means less opportunity for a stone to fly up and break their windscreen. This has an impact on business."
Also having a significant effect on business - albeit more positively - is their renowned advertising jingle. Starting in Belgium eight years ago, within two years the advert was running in 20 countries. It is the same in every one but featuring a local technician and different brand name.
He says: "The jingle, which I know irritates a lot of people because they hear it so much, has been extremely powerful. I love that my son hears it being sung by his friends because it's catchy.
"There is no question that it has driven growth in all our countries. We can see a direct effect of our advertising on our brand awareness." Just as well. Belron spends £150 million worldwide a year on it. Their advertising budget has doubled over the past few years. "If you have effective advertising, you should be increasing it," he says.
Autoglass rivals include National Windscreens and more recently, the AA, but the Belron group as a whole remains relatively unchallenged. Their main competitor, Auto Windscreens, recently went into receivership. But Mr Lubner, who travels every week for work, is not getting complacent. He is keen to expand both new and existing markets - they recently entered China and Russia.
Despite the global expansion and being majority-owned by Belgium company D'Ieteren, the company's family roots are still very much reflected in the business, not least in the name, which is after Gary's grandmother 'Bella' and father 'Ronnie'. Mr Lubner explains: "The initial plan was to name it after my father Ronnie and grandfather Morrie. But when we put those two together, it came out as 'moron'. We thought that wasn't such a good idea."
He places great emphasis on corporate responsibility. "It's an inherent part of our values. My family were always very charitable and we believe that an organisation has an obligation to the communities they service. I am passionate about tikkun olam and Jewish charities reaching out."
For the past ten years, Belron employees have participated in the London Triathlon to raise money for MaAfrika Tikkun, a South African charity co-founded by Mr Lubner's uncle Bertie that provides support to vulnerable children. Last year, 900 Belron employees from 18 countries raised £600,000. It was the largest corporate entry into any sports event in the world. Mr Lubner is hoping for 1,000 participants this year.
So, has Mr Lubner, a member of Alyth Gardens Synagogue in north London, ever used his company's service? Yes, when his car was broken into outside his Hampstead home.
