Today Hwang oversees a lab that cloned the first human embryo as part of medical research, establishing his facility as one of the world leaders in stem cell research.
At one of his labs in a veterinary building at Seoul National University, Hwang stands beside a display of stem cells his team created by taking a piece of skin from a patient to create stem cells that are genetically identical to that of the donor.
"These are the first of the kind in the world," Hwang said on Sunday.
He wears a blue moon-suit, drenched in sweat from sweltering heat as his team battles three hours with no ventilation in a power outage - with just essential equipment running off a generator.
Stem cells have the ability to transform themselves into many other types of cells and offer the potential of regenerating damaged organs or tissue.
Reservoir of cells
A stem cell line is a reservoir of stem cells derived from a single human embryo. "We can increase the number of stem cells by 15 times in one week," Hwang said.
Hwang, 52, oversees a team of 45 researchers. He has an office and a lab located on the sixth floor of the bureaucratically named University Building Number 85.
Hwang spends about 16 to 20
hours a day in his laboratory
At one table, about 15 researchers extract eggs from cow ovaries. Each morning, some of them can be seen hunting for the organs at local wholesale butchers. They transport them to the lab swiftly in thermal containers.
In another room, a technician is using a high-powered microscope and delicate controls to manipulate a microneedle.
She positions a cow egg against a glass pipette to pluck the membrane and squeeze out the cell's nuclear material.
Next to her, another technician inserts nuclear material that will be used for cloning into a different cell that has been stripped of its genetic material. Hwang's lab can process up to 1400 eggs a day.
This is all a far cry from his early years. Hwang's father died when he was five, and he was at times forced to eat tree bark as his family battled poverty in post-war South Korea.
"As a child, I dreamed of becoming a veterinarian," he said. Today, he says, his goal is to realise the dream of mankind and open a new era in medical science.
"We all put in a five-day week. We work Monday, Tuesday, Wednesday, Thursday, Friday, Friday and Friday"
joke at Hwang's facility
Hwang, quick with a smile and concise in his words, worked on cloning animals from 1999. He led the cloning of a type of cow in 2003 that would be resistant to mad cow disease.
"I saw that my research had the potential to benefit humans," Hwang said about his decision to work with stem cells.
Work starts at about 5.30am for Hwang, and he will pause for meditation and then spend about 16 hours to 20 hours in the lab. The team steals quick meals at cafeterias around the sprawling campus, but Hwang remembers to treat them to an occasional barbecue, researchers say.
The joke around the facility stocked full of workaholics, such as Hwang: "We all put in a five-day week. We work Monday, Tuesday, Wednesday, Thursday, Friday, Friday and Friday."