If Detroit is holding its breath right now over Dan Gilbert's health crisis, there's a good reason.

Many corporate benefactors have boosted Detroit over the decades, from Henry Ford II to Mike Ilitch. But no one in that league has ever had the impact Gilbert has had in less than 10 years.

Since moving his Quicken Loans headquarters downtown in August 2010 with an initial roster of 1,700 employees, Gilbert has unleashed an astonishing array of real estate deals and streetscape transformations. They made him, as much as anyone, the face of the city's comeback.

His workforce downtown has swelled to 17,000, a key reason why downtown swarms these days with young people riding scooters or queuing up at the food trucks around Campus Martius Park.

Gilbert famously went on a buying spree for aging and often empty skyscrapers. But unlike many earlier buyers that sat on such buildings for years, Gilbert and his team at his Bedrock real estate arm quickly filled many of them with new tenants. Vacancy rates plummeted and rental rates rose.

Long-vacant retail storefronts along Woodward began to fill with stylish retailers as Gilbert and his team curated a new shopping experience. That retail effort ratcheted even higher with the annual holiday markets that have become an instant downtown tradition.

"I think he's made a tremendous transformational impact on the city and downtown over the last not quite 10 years," said Bob Gregory, chief planning and public space officer for the Downtown Detroit Partnership. "It starts with his commitment to the city and to downtown in a very comprehensive and passionate way."

Gilbert suffered a stroke Sunday after going to Beaumont Hospital in Royal Oak complaining of feeling poorly. Jay Farner, CEO of Quicken Loans, said he visited Gilbert in the hospital on Monday and told reporters Tuesday, "He's resting and recovering and improving by the hour."

Hudson's site

Gilbert took on the toughest of the redevelopment challenges — the old Hudson's block, where the city's tallest new building is in the early stages of construction, and the notorious "fail jail" site off Gratiot that he took over from Wayne County in exchange for agreeing to build a new criminal justice complex in Midtown.

In everything from promoting downtown murals to buying the naming rights for the QLINE, Gilbert has been a driving force behind downtown's newly interesting walkable streetscapes.

He didn't do it alone, of course. Among others, the Michigan Legislature passed new tax incentives at his urging and the Michigan Strategic Fund then approved the state's biggest-ever tax breaks for his major downtown projects.

Then, too, Mayor Mike Duggan's administration got behind Gilbert's plans, and civic groups including the Downtown Detroit Partnership and the philanthropic leader Kresge Foundation contributed mightily to the city's recovery with money and leadership, as did many others.

But by turns upbeat, volatile and childlike in his enthusiasms, Gilbert has been the driving force behind many of the positive trends we see. He seemed to touch everything, from residential developments like his City Modern project in Brush Park to the rise of a new tech culture with startups like StockX, the sneaker and luxury goods exchange.

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Behind the scenes and in public

And beyond the obvious downtown projects, there were lesser known moves to benefit the city. His Bedrock team worked with the Detroit Land Bank Authority to fund the Rehab & Ready program that fixes up houses in distressed neighborhoods to jump start housing values. His workers volunteered to digitize Detroit Public School graduation records so employers could verify an applicant's record more easily.

And unlike most billionaires, Gilbert did not absent himself from public view. Rather, he seemed to be out in public all the time, at courtside for his Cleveland Cavaliers games, speaking at Detroit Regional Chamber events, cutting ribbons or turning the first shovel of dirt at his groundbreakings.

And rather than insulating himself with a phalanx of public relations spokespeople as many billionaires do, Gilbert granted frequent interviews. Indeed, he is known to pick up the phone and call or text reporters when he is happy or irate over a story.

No one says all this grinds to a halt because of the stroke Gilbert, 57, suffered Sunday while being examined at Beaumont Hospital in Royal Oak. Indeed, his company's official statement on Gilbert's health emphasized that the leadership team at Quicken, Bedrock, Rock Ventures and other parts of Gilbert's empire would go on operating normally as Gilbert recovers.

And the company emphasized that the immediate medical intervention helped Gilbert, who was said to be awake and resting comfortably and on the road to recovery.

But anyone who has observed Gilbert over the years knows that he is the classic founder, owner and entrepreneur — deeply involved in all aspects of his business, demanding of his team, the driving force behind all his downtown revival efforts. If he's absent for any significant length of time, it seems inevitable that it would affect his many efforts.

So for Detroit's sake as well as his own and his family's, the sooner Gilbert is up and around again, the happier Detroit will be.

Contact John Gallagher:313-222-5173 or gallagher@freepress.com.Follow him on Twitter@jgallagherfreep. Read more on business and sign up for our business newsletter.