I told everyone, ‘We’re going to take this house back to the year it was built — 1770,’ ” he said, as horse-drawn carriages filled with tourists passed by outside on a spring Friday. It took three years, but Mr. Dewberry, 45, the chief executive of Dewberry Capital Corporation, a commercial real estate company, now has the house he envisioned. It is a luxurious 21st-century home within an 18th-century structure, architecturally correct down to the proper hand-tooling of masonry grout. Brick makers, furniture makers, wrought-iron craftsmen, masons, coppersmiths, stoneworkers, even interns from three colleges — 32 people in all — helped Mr. Dewberry turn back time. They removed every element that wasn’t era-appropriate. What they couldn’t restore, they recreated in minute detail. Four months of research preceded the start of the project. “John was committed to doing the research necessary to document the structure,” said James Meadors, the owner of Meadors Construction, which specializes in restoring historic architecture. “He wanted to be the current steward of the house and preserve it.” What stands today is a 5,000-square-foot structure that has been returned to its original Georgian dimensions, its floors raised nearly two feet to correct an earlier modification, windows replaced with taller ones of period size, and brick that was either salvaged or fashioned to look 250 years old. Cypress walls and floors reflect the patina of age — real or faux. Bluestone in the garden patio has replaced cement. Flickering copper gas lanterns frame the door. Mr. Dewberry searched for eight years before settling on the three-story house on Meeting Street, a few blocks from Charleston’s waterfront. It had languished on the market, and for good reason. While it had a pedigree, having been the home of Henry William de Saussure, a director of the United States Mint under George Washington, it had also been a corner store for 100 years. Several ill-advised renovations later, the house needed a buyer with patience and deep pockets. Mr. Dewberry bought it for $1.5 million. Two months into the renovation, he realized the project was far bigger in scope than he had imagined, and to “get it right” — a favorite phrase of Mr. Dewberry’s — it would take longer and cost more. The price tag? More than twice the cost of the house itself. Mr. Dewberry’s primary home in Atlanta is a ranch house retooled to resemble a mountain lodge, but as a history buff, he was enchanted by Charleston’s past. “I always said, ‘If I do well enough, I’d love to have a house in downtown Charleston,’ ” he said. By almost any account, he has done more than well enough. Dewberry Capital develops office buildings, mixed-use retail space and hotels, and has $500 million in owned assets. He has also been a player of a different sort. Mr. Dewberry was a starting quarterback for Georgia Tech in the mid-1980s. He financed his company after college with a $5,000 signing bonus from the Calgary Stampeders of the Canadian Football League. As Mr. Dewberry led a tour through the house, he flashed a guileless charm combined with the Southern swagger of a Ted Turner and the relentless pitch of a Donald Trump. But he has not been immune to misfortune. In July 2008, he received a diagnosis of prostate cancer. Five months later, he appeared on an Atlanta news program to talk about his illness — an appearance he felt was imperative. “It’s not just the right thing to do, it’s the only thing to do,” he said on the program, on WSB-TV. In April, his doctor declared him cancer-free, and he is taking only hormone therapy. “No one wants cancer,” Mr. Dewberry said, “but the outpouring of good wishes has released a lot of good karma into the world. I was grateful to understand how many people cared deeply about my well-being.” Despite a penchant for accuracy and a love of history, he has neither turned the house into a museum nor sacrificed contemporary comforts. “I live in every room,” said Mr. Dewberry, who visits Charleston once or twice a month.