All cities have their corporate benefactors, but few enjoy one quite like Detroit's Dan Gilbert. Founder and chairman of Quicken Loans, the online mortgage giant, Gilbert moved his corporate headquarters from a suburban office park to downtown Detroit in mid-2010. Fired by a vision of remaking Detroit's tattered image, he embarked on a shopping spree for undervalued skyscrapers, snapping up dozens of properties in the city's core.

Gilbert's holdings now include some of Detroit's most notable architectural landmarks, including One Woodward, First National, Chase Tower, and Book Building. He owns the Greektown Casino, and he controls through master leases virtually all of the retail space along Woodward Avenue, the city's main street. His holdings now total nearly 100 properties, and Forbes magazine estimates his wealth at $3.8 billion.

That he was able to grab so much so fast says as much about the depressed values of Detroit real estate as it does about Gilbert's own outsized ambitions. But it also upends the usual model of downtown redevelopment, which relies on the local municipality wooing a host of different developers with generous tax breaks on a project-by-project basis. Perhaps Gilbert is a version of the "great man" theory of history: that one visionary individual wielding power and money can do as much to stimulate growth as any city plan­ning commission could.

To be sure, not all Detroiters are convinced that this "great man" is also a good man. That so much has happened in just five years has left Detroiters a little stunned. Critics grumble about one man controlling so much, and his focus on downtown has spurred a gentrification debate similar to (if not yet on the scale of) that taking place in other cities.

Even so, Gilbert, 54, retains the solid backing of Detroit's political and business classes. And although he's not the only important property owner or player in Detroit, it's getting hard to argue with the nick­name that wags are attaching to the city's central core: "Gilbertville."

Many of the properties he purchased were half-filled at best when Gilbert got them. Today, the 1,500-person workforce he brought downtown with him in 2010 has swelled to about 12,000, and those underused downtown towers have filled up with educated millennials with disposable incomes.

Teaming with Project for Public Spaces in New York City, Gilbert has enlivened Detroit's downtown with placemaking tactics that include a beach volleyball patch in summer and a host of new retailers, coffee shops, and eateries. Also in the works: a signature architectural statement now being designed by SHoP Architects for an important site once occupied by Detroit's iconic Hudson's department store, which was imploded in 1998. Gilbert has moved into the civic space, too. He co-chaired the city's blight removal task force that strategized how to deal with the city's thousands of vacant eyesores. He helped pay for the much-praised Motor City Mapping endeavor that created the city's most accurate database ever of its 380,000 or so parcels. He was a financial contributor to Detroit's "grand bargain," the philanthropic effort to save the pensions of municipal retirees and the art collection at the Detroit Institute of Arts during the city's recent bankruptcy. And he is a sponsor of the city's M-1 RAIL streetcar line, due to begin operation in 2017. When that streetcar service starts, it will be under a yet-to-be-revealed name that Gilbert will get to choose — since he also bought the naming rights.