CHICAGO — Former White House chief of staff Rahm Emanuel announced Sunday that he's preparing to run for mayor of Chicago, a position it was widely known he has long desired.Emanuel made the announcement in a video posted Sunday on his website, ChicagoforRahm.com. He had been careful not to launch his candidacy from Washington and headed to Chicago immediately after President Barack Obama announced his resignation Friday.RELATED:Emanuel to run for Chicago mayor; replaced by RouseEmanuel bar mitzva followed by mitzvaIn the video, Emanuel said he's launching a "Tell It Like It Is" listening tour of Chicago."As I prepare to run for mayor, I'm going to spend the next few weeks visiting our neighborhoods — at grocery stores, L stops, bowling alleys, and hot dog stands," Emanuel said.The two-minute video shows a relaxed Emanuel sitting behind a desk wearing a white shirt that's open at the collar and a dark jacket. Behind him is a photo of his family and several books.One of the challenges facing him in a mayoral run is reconnecting with Chicago voters after his time in Washington. Emanuel highlighted his ties to Chicago in the video, noting his three terms representing a North Side district in Congress before serving as Obama's chief of staff."It was a great honor to work for (Obama), but I'm glad to be home," Emanuel said. Emanuel joins a crowded field of Democrats who have announced they're running for mayor or hinted at it. Among them are Gery Chico, the Chicago School Board president and a close Daley ally; Cook County Sheriff Tom Dart, and State Sen. James Meeks, who's also the pastor of a South Side church.