But many tasks that typically fall to a managing director are now done by one of the city's deputy mayors, who report to both Barnett and Mayor Nutter.
For example, last year, when the city managed a massive parade in honor of the World Series-winning Phillies, the deputy mayor for transportation and public utilities, Rina Cutler, took media questions on the post-parade cleanup.
During the controversial attempt last fall to close city libraries, the deputy mayor for health and opportunity, Don Schwartz, was front and center.
And currently, the deputy mayor for public safety, Everett Gillison, is in charge of preparation for a potential city workers strike.
"By charter the managing director is really the chief operating officer of the city, but that's been less and less the case," said Zack Stalberg, chief executive officer of the Committee of Seventy, a political-watchdog group.
"It seems as if Dr. Barnett is not really playing that role. Whether it's the mayor's choice or her choice, she seems to take on these singular projects."
Barnett said she supports the setup, which gives more authority to the deputy mayors, noting that it is a common governing structure in other cities.
"I think one of the things this organization does is strengthen the executive function," Barnett said. "I'm a supporter of the deputy-mayor concept."
Asked if she thought the responsibilities awarded the deputy mayors diminished her role in the government, Barnett said: "I don't view power as a zero-sum game."
Nutter agreed that he had organized his government to spread some of those responsibilities around, but stressed that this system meant that Barnett could focus more time on government reform.
"We've empowered numerous high-level officials in the government. It's shared responsibility and process," Nutter said. "I think what it does is free up [Barnett] to work on a variety of the reform efforts. "
Given that it's only 18 months into Nutter's first term and that the city is gripped by a massive fiscal crisis, it is hard to fully assess Barnett's performance. But it is clear she is not operating in the public eye as previous chief operating officers did.
W. Wilson Goode - who was managing director under Mayor Bill Green - rose from that job to the mayor's office. Known for working long hours, Goode was credited with cutting city costs and negotiating contracts with wage freezes for blue- and white-collar workers.
More recently, under Mayor John Street, Phil Goldsmith and his successor, Pedro Ramos, were both visible presences at fires or flood scenes.
"You're always on," Goldsmith said. "You have your in-office hours and then, even on vacation, you're waiting for the phone to ring."
You have to look back to Gene Shipman, who was lampooned as an "invisible man" during his two years as managing director under Mayor Ed Rendell to find a chief operating officer with a lower profile than Barnett.
Barnett, who speaks with a Southern twang and favors flowing scarfs and knee-length cardigans over power suits, was hailed as a new kind of city manager - one who would focus on government efficiency - by Nutter when he tapped her for the job in 2007.
At the time, Nutter declared that he had "asked Camille to come here to make this city work and run."
Her last job was with Philadelphia-based Public Financial Management in its Washington office.
Barnett left her last two public jobs under difficult circumstances.
In Austin, where she served as the city's top manager, she left after it was discovered that a city-owned hospital for which she was responsible was running a $21 million deficit.
And in Washington, she resigned as chief management officer after only a year, under criticism that she hadn't improved services rapidly enough.
Barnett was hired by Nutter at $195,000 a year, but this year she's set to make $178,555, according to payroll records, due to pay cuts taken by top staffers in light of the budget crisis. She has the sixth-highest salary in the city, and it is higher than the legally established maximum for the job. Nutter gave her an extra title to get around the cap.
Barnett's transition to Philadelphia from Washington was interrupted by tragedy. Her husband was killed in a car accident in January 2008, as he was transporting some of the couple's belongings to Philadelphia.
"The biggest transition I've had to make here was a personal one," Barnett said. "Dealing with all the changes in my personal life and a global economic crisis has been a little bit of a challenge."
She has devoted her first year on the job to getting two programs up and running - the 3-1-1 nonemergency-call line, which launched in January, and the PhillyStat data-tracking system.
The 3-1-1 line took a year to get going, as promised, but budget constraints limited the hiring and equipment purchased. Currently wait times can be as much as five minutes.
City Councilman Jim Kenney, a longtime advocate of 3-1-1, said: "Having one number to call, I think that's been successful."
PhillyStat has been in place for more than a year. Under the program, departments are regularly summoned to the Municipal Services Building, across from City Hall, where they present slides on their performance and budget before Barnett and her staff.
"I think the thing PhillyStat has done mostly is to establish the new way of judging success, which is [that] it needs to be measurable so we're more performance-oriented," Barnett said.
Asked for an example of a policy change made by the city due to PhillyStat data collection, Barnett noted that last year the city collated information on summer programs from various agencies into one guide for citywide use. She also said that PhillyStat data was used last November in deciding where to cut the budget.
But sometimes the data-tracking process has a few holes.
For example, a recent presentation on the 3-1-1 call line said that the city had exceeded expectations, with 600,000 calls in the first six months, even though the call-center director told the Daily News in November that she was budgeting for 1.5 million calls in the first year.
Barnett said that perhaps there had been a change in the initial estimates, causing the confusion.
With 3-1-1 and PhillyStat set up, Barnett said she will continue to work on improving efficiency and customer service.
She laughed off questions about her visibility and role in the government, saying she was just keeping her head down and plowing ahead.
"I do think we are moving in the right direction," she said.