He'd been born into a time when Chinese people were enduring mass hardships, including famine and the fallout from the Cultural Revolution. Hard work and suffering were commonplace and basic items such as cooking oil and salt were considered a luxury.
"We survived on cheap cereal crops throughout the year. We were slightly better off than our neighbours, because my parents were teachers," says Ren. "By better off, I mean we could add salt when we cooked."
However, the challenges and difficulties have not stopped now that Huawei has attained global status – passing Apple as the world's number two smart phone brand and the world's biggest manufacturer of network equipment for the world's telcos.
One of those current challenges is that his daughter, Meng Wanzhou, is being held in Canada on US charges she helped violate sanctions against Iran.
In one interview, Ren says: "For three decades, Huawei has been suffering and no joy. The pain of each episode is different."
However, he has some experience of pain. One of seven children raised by schoolteachers who managed to feed the family on a monthly wage of 40 yuan – his mother told biographer Tian Tao, co-author of The Huawei Story, that she painstakingly divided each meal into nine small portions, so no one would die.
In the army, he endured freezing conditions (sometimes -28C) and poor food when helping to build houses in the far north of China – also a time when he began to develop his engineering skills and powers of innovation.
In 2000, in a key episode of Huawei's evolution, Ren resisted developing the personal handy-phone system (PHS) as a low-cost alternative to mobile service. Ren rejected PHS as a distraction from work on next-generation mobile technology that promised to be cheaper and more reliable.
It was a key decision, though Ren had to withstand appeals to back PHS as bills for 3G development rose to 6 billion yuan ($1.1 billion)
In another interview, Ren said: "Today's crisis is one-tenth or 1 per cent of the pressure at that time. Tian said Huawei employees told him Ren, unable to sleep, would call and worry aloud about how to pay a 300 million yuan ($77m) monthly wage bill.
Before the US sanctions, sales last year rose almost 20 per cent to US$105bn ($161bn) and Ren has steered Huawei towards becoming a self-reliant, self-contained technology creator – including work on an operating system (Harmony OS) which can power smartphones and other devices. This year's research spending is due to rise 20 per cent to $17 billion ($26bn).
