"To speak on the same night, in the same arena, as President Barack Obama? I mean it's just something way beyond anything that I could have imagined as a [kid] running around 55th and Larchwood out in West Philadelphia," Nutter said.
His speech has been vetted ("very much so") by the Obama campaign, the mayor said. He wouldn't give a taste of what is to come, but said "it will be clear and factual and direct."
Nutter's strut on the national stage could be viewed as significant for those theorizing that he could leave office early and take a high-level job in Obama's second term.
Rep. Chaka Fattah (D., Phila.) - who once ran against Nutter - said in an interview on the convention floor that he sees Nutter's speech as "part of a continuum of the mayor moving increasingly into both substantive and symbolic roles on the national stage."
Fattah said Nutter had built bridges that help him politically while also aiding policy pursuits in the city, and that his growing national role "will benefit him no matter what his future may be, whether that's in the cabinet, whether that's in running for federal or state or other office."
Within the Democratic family, Nutter had been seen as a Clinton man. He actually ran in 1992 as a Pennsylvania delegate for presidential candidate Bill Clinton, then a little-known Arkansas governor - a fact that Nutter said he reminisced about with Clinton on Tuesday.
And Nutter endorsed Hillary Rodham Clinton, then the New York senator, when she ran against Obama in the 2008 Democratic primaries.
But while he said he has "a very strong relationship" with the Clintons, he has a "growing and developing relationship" with the Obamas.
That doesn't mean he's moving to Washington if Obama wins. "I'm very focused on my job as mayor of the city of Philadelphia," he said. "I have no expectations for the future. I don't expect to be asked."
Regardless of his political future, a little national visibility in Charlotte can't hurt. Walking down one street near the convention Wednesday afternoon, he didn't seem to be recognized by a single Democrat.
He was accompanied by a security detail; his wife, Lisa; a representative from the Obama campaign; and a staffer who carried a large blue binder with a list of the events he is attending or speaking at this week.
And a stuffed binder it was: As Nutter explained, he must juggle responsibilities here as Democratic officeholder (he spoke to the Pennsylvania delegation Tuesday morning), as an Obama surrogate (he appeared on CNN this week), and as president of the nonpartisan U.S. Conference of Mayors.
Addressing the Pennsylvania delegation, Nutter fired up the partisans about the president: "Wanna know how tough he is? Ask Osama bin Laden how tough Barack Obama is."
Later, in a more cerebral appearance on a panel with the mayors of Charlotte, Houston, and Florence, Italy, Nutter reflected on the challenges and opportunities of running a big city.
He spoke broadly of cities as "incubators of innovation" and specifically about his effort to make Philadelphia the greenest city in the country.
Nutter also responded to an article in The Inquirer on Wednesday that noted the possible $10,000 cost to taxpayers for his convention trip.
"I should just stay in my office for about 18 hours a day and never see anyone," he said sarcastically, to laughter from his audience.
He proceeded to tick off the ideas he had learned by traveling the country and talking to other mayors, thus making it increasingly clear that staying put in City Hall is not on the mayor's schedule.
Contact Matt Katz
at 609-217-8355 or email@example.com, or follow on Twitter @mattkatz00. Read his blog, "Christie Chronicles," at www.philly.com/christiechronicles