Mayor Rahm Emanuel's communication chief Chris Mather is moving on, after launching a City Hall press shop yielding Emanuel enormous positive local and national coverage almost every day since he was sworn-in on May 16.

Mather returned to Chicago earlier this year from Washington, where she served in the Obama administration as communications director for Agriculture Secretary Tom Vilsack. Before that, she was press secretary for Jill Biden during the 2008 presidential campaign. Ironic: When Emanuel made his first run for Congress, Mather was the campaign manager for his chief rival, Nancy Kaszak.

Mather is the first departure of a major Emanuel staffer. No word yet on her next gig; as a veteran of the Obama administration and Emanuel City Hall she is considering a number of options.

"While it was difficult to leave the Obama Administration, I was thrilled to be offered the opportunity to come back home and help ensure Mayor Emanuel's smooth transition at a time when Chicago faced enormous challenges," Mather told me on Thursday.

"I am extremely proud of the work we have done in the Mayor's first year for the people of Chicago and I am also proud of the work I was able to do on his behalf. I leave knowing we accomplished what we set out to do in this first year, building a strong communications operation that will serve the Mayor and the City of Chicago well for years to come. As I look back on this first year, I have many fond memories of working with Mayor Emanuel and I will forever be a friend and ally.

"While the press corps might not believe it, I have thoroughly enjoyed working with them and consider many of them my friends. I look forward to continuing those relationships in my next role.

"Helping Mayor Emanuel hit the ground running has been an all-consuming, 24-7 job but one I have truly enjoyed and thoroughly appreciated. I wish the Mayor and his team the best of luck."