Sitting in his office one afternoon last week, Mayor Kenney said all of the praise he had received for a successful first seven months on the job was making him a bit uneasy.

"Being Irish, I don't like that," Kenney quipped. "Because then that means something bad is going to happen."

Two days later, the FBI was swarming the home and office of one of Kenney's closest political allies, Electricians union leader John "Johnny Doc" Dougherty, in an investigation a source said touches on the union's financial support of Kenney's mayoral campaign.

Now, after executing a promising opening to his administration, Kenney is awaiting any fallout from the probe. Dougherty has not been criminally charged, but the investigation could dim the glowing reviews of Kenney's time in office.

The mayor this week repeated that he had no indication that the investigation was about him and that it had no impact on his record.

"Everything we've done in seven months, I think, has been stark and positive for the future of the city," Kenney said. "Any shadow being cast? There's no light at the moment to cast a shadow."

Others say the many questions surrounding the FBI's inquiry will keep Kenney in the spotlight - perhaps unjustly and only for a time.

"It's exactly the lack of certainty and the lack of clarity in regards to the scope and the focus of the investigation that allows this to linger over the whole city, for as long as it takes for them to tell us what they're looking at," political consultant Mark Nevins said. And that could be years, as witnessed by the recent conviction of U.S. Rep. Chaka Fattah, the subject of a lengthy federal investigation.

Kenney's administration had received nearly flawless reviews. The mayor, who turned 58 Sunday, had drawn praise for his progressive agenda, his political savvy, and, considering his history as a short-fused city councilman, his temperament.

Administration highlights include passage of a sweetened-drink tax to fund early childhood education and a well-run, peaceful Democratic National Convention.

David L. Cohen, a Comcast Corp. executive and chief of staff during Ed Rendell's mayoral administration, said Kenney's performance had been "outstanding."

"Really, in every respect you could grade it," he added.

David Thornburgh, president of the government watchdog Committee of Seventy, said Kenney had "projected a sense of calm" in high-stakes situations. He pointed to the recent smooth contract negotiations between the city and its largest union, and the debate over the beverage tax, which "could have turned into a holy war" but did not.

"People appreciate that - the sense that the city administration is not a series of high-drama cliff-hangers," Thornburgh said.

But Kenney did not earn solid reviews solely through a lack of risk. His time in office has been bookended by endeavors with far-from-certain outcomes.

One he brought on himself (proposing to expand early childhood education with a tax on sugary drinks) and the other was on his calendar from day one (hosting the convention). Experts say he handled both with aplomb.

On the soda tax, the first of its kind enacted in a major U.S. city, Kenney used his relationship with City Council to his advantage and courted votes one by one. He also made an unusual pitch by tying the tax not to health benefits but to the programs it would pay for.

That gave Council, which had twice rejected similar proposals, a reason to take a fresh look. And when the 1.5-cent-per-ounce tax passed, it prompted elected officials and reporters around the country to wonder how Kenney beat the soda industry - backed by a $10.6 million campaign - where so many others had failed.

The win also highlighted a level of cooperation between the mayor's office and Council that was nonexistent during the Nutter administration. Kenney's national stock rose again as the convention went off without a hitch.

The challenge of having 50,000 visitors flood one's city was significant enough. Adding to that was the backdrop of tension nationwide between police and protesters.

Philadelphia's Police Department performed well under the pressure and helped de-escalate heated situations. Rather than making arrests, police handed out civil citations, something possible because Kenney had backed a proposal from one of his police captains to decriminalize disorderly conduct ahead of the convention.

"He gets all the credit for the cops, all the credit in the world," said Dan Fee, a Democratic political strategist who specializes in political campaigns and knows the mayor but has never worked for him. "Because they directly report to him, and it was a very clear mandate - that this is going to go well. We will not have problems. Period."

Kenney has not escaped criticism. He drew fire last month when the head of the Catholic League accused him of "misusing his public office" after the mayor challenged Philadelphia Archbishop Charles J. Chaput's guidelines on who can receive Communion. Kenney said the guidelines were "not Christian."

In May, the surly attitude Kenney was known for on Council was seen when he kicked out a group of reporters who had been invited to join him on a tour of one of the city's prisons. At the time, his staff said he was concerned about inmates' privacy.

Now, there is Dougherty.

Kenney came into office facing questions about his relationship with the union boss. In addition to raiding Dougherty's home and office, the FBI also searched the City Hall office of Council Majority Leader Bobby Henon, who is on the union payroll and is an ally of Kenney's.

Several political experts on Monday said it was too early to tell if the investigation will prove to be a serious problem for Kenney. Political consultant Ken Smukler said it could help him in the short term, should Dougherty decide to lay low for a while.

"That could actually prove to be liberating for Jimmy," Smukler said. "I don't know what Jimmy's agenda is and I don't know if that agenda dovetails with Johnny's agenda. But if it didn't and now Johnny is on the sideline, that could be a plus for Jimmy."

Others were not as optimistic. Sam Katz, a former Republican mayoral candidate, said it was too early to make judgments but that any FBI investigation targeting the city is bad news for a mayor.

"When you raid a person's home and business, you don't necessarily draw a tie to the government," Katz said. "You raid the offices of a prominent leader of the city government, it's hard to ignore they're looking at the ties between labor and government."

tnadolny@phillynews.com215-854-2730 @TriciaNadolny