Eighteen months after a ceremonial groundbreaking on a dreary December day, McDonald’s on Monday chose a picture-perfect day to open its new corporate headquarters on a West Loop site that once housed Oprah Winfrey’s Harpo Studios.

“We are welcoming home the most iconic American business to the most American of American cities,” Mayor Rahm Emanuel told assembled movers-and-shakers.

Noting that McDonald’s was headquartered in Chicago from 1955 to 1971 before moving to Oakbrook, the mayor said, “I want to say to the 2,000 employees at McDonald’s, Welcome home….Now that you’re here, we’re not letting you go ever again.”

McDonald’s CEO Steve Easterbrook said his employees made the move to the nine-story building at Randolph and Carpenter by two moving days-a-week over the last month.

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Their reaction to an urban headquarters that couldn’t be more different than the bucolic suburban campus they left behind underscored McDonald’s reason for returning to Chicago without an incentive or subsidy of any kind.

In addition to the 2,000 corporate employees, the new building will also house an updated version of the company’s Hamburger University training center.

Mayor Rahm Emanuel talks to McDonald's CEO Steve Easterbrook at Monday's grand opening of the company's new corporate headquarters in the West Loop. | Fran Spielman

Mayor Rahm Emanuel talks to McDonald’s CEO Steve Easterbrook at Monday’s grand opening of the company’s new corporate headquarters in the West Loop. | Fran Spielman

“Sometimes, I’ll just sit on the sixth floor in the work café area and see the tours go around and just see smiles on peoples’ faces in a way that’s hard to replicate in a rather more old-fashioned office. The environment is already making a difference,” Easterbrook said.

To ensure long-term success, Easterbrook said McDonald’s needs to “innovate” and “satisfy customers and their ever-changing needs.”

“We firmly believe that part of the importance of the move to downtown is that it gets us closer to our customers…It gets us closer to the competition. It gets us closer to the trends that are shaping the future of society…,” he said.

Developed by Sterling Bay, the building includes what McDonald’s is calling “work neighborhoods” with open floor plans that allow employees to choose the environment that best fits their needs.

In addition to traditional work stations, the choices include: huddle rooms; communal tables; private phone rooms; outdoor terrace spaces; a 700 person conference center; and a work café billed as the “ultimate collaboration space” with stadium seating “designed to represent the colorful tube/tunnels in a PlayPlace.”

The new building also includes a ninth-floor fitness center with views of the Chicago skyline and museum-like tributes throughout to the rich history of the company founded by Ray Kroc.

Brittany McDonough, co-chair of McDonald’s Young Professionals Network, said she knew that moving downtown would be a big change. But she had no idea how “significantly different” the new building would be.

“The energy has changed. A big part of that is, of course, the location. How could you not love the West Loop? But more so, the various workspace options we have that caters to all work styles,” she said.

“Those touch points with your team and even leadership are so much more frequent. It’s night and day. What would have usually taken a day or two to connect or get on somebody’s calendar is now happening organically in the hallways, in the neighborhoods and those various workspace stations.”

Monday’s grand opening featured free samples from a ground-floor McDonald’s restaurant with its rotating menu of food items from around the world. There was also an electronic button-pushing that dropped the, “Home Sweet Home” banner to expose the building’s glistening facade.

It was yet another reunion of sorts for Emanuel and Robert Gibbs, executive vice president and global chief communications officer for McDonald’s.

Emanuel and Gibbs served together under President Barack Obama. Gibbs was White House press secretary. Emanuel was Obama’s first White House chief of staff.

Now, the two men are neighbors in Ravenswood.

“We are thrilled to be back in Chicago. We are thrilled to be in its most vibrant neighborhood,” Gibbs said.

Emanuel noted that the McDonald’s project generated $3.2 million for the fund created to rebuild impoverished neighborhoods with share-the-wealth contributions from developers allowed to build bigger and taller projects in a broader downtown area.

“It was Steve’s desire when he read about it to be the first business,” Emanuel said of Easterbrook.

“I don’t know if that’s what hooked him because I don’t want to go through another corporate meeting to discuss this to be honest. But I’m so glad it happened.”