Sean Matteson could be doing more important things with his time.

The 37-year-old mayoral chief of staff swivels in his chair like a restless teenager, no doubt frustrated to be wasting half an hour with a reporter. His eyes flick from any of several gaudy Post-it notes affixed to his computer screen to the two cell phones lying by his keyboard. His left hand taps against a drained can of Coca-Cola.

“I’m exhausted,” Matteson says.

With good reason. As chief of staff to New Haven Mayor John DeStefano Jr., Matteson acts as political stage manager, coordinating the mayor’s top lieutenants and shepherding initiatives through City Hall until they are ready to arrive on the mayor’s desk. As he enters his ninth month in the job, his colleagues say he has adjusted well to City Hall and has wowed them with his work ethic.

Even with four kids and a wife at home, Matteson often doesn’t leave work until 10:00 or 11:00 p.m. In the morning, he steps into his office around 6:00 a.m., although every now and again he pushes that back an hour or two.

“I try to let the mayor beat me here one day a week because it makes him feel good,” he said.

It is a jab tempered by their strong working relationship. The two met years ago when Matteson was working for the Hotel Employees and Restaurant Employees International Union, or HERE.

“My first impression [of DeStefano] was that he seemed very knowledgeable,” says Matteson. “So I took leave from the union and worked on his gubernatorial campaign.”

That campaign, which ended in defeat on Election Night 2006, produced two things: a friendship, and an invitation to return to New Haven as chief of staff.

Since then, Matteson has been learning the ropes of managing a sizeable urban bureaucracy and seems to have mastered them quickly.

“He’s a great guy to learn from,” said Deputy Chief of Staff Paul Nunez Jr. “He knows how to assess situations — when to drop the hammer and when to just let things slide and work themselves out.”

Nevertheless, Matteson admits there have been difficulties. Matteson suspects that his relative naivete when it comes to bureaucracy was part of why he was picked for the job.

“I think [DeStefano] wanted something from the outside,” Matteson says. “I wasn’t a product of the administration. I wasn’t an alderperson. I didn’t graduate from Yale. I tended to be exotic.”

Matteson’s arrival to City Hall followed the departure of Karen DuBois-Walton, who became deputy director of the city’s Housing Authority in January after two years as chief of staff.

“[The hardest part] is learning the intricacies of government and how each department relates to one another, getting to know folks,” Matteson said. “For some, putting the fear of God in them and doing so in a way that hopefully expedites matters.”

City bureaucracy is new for Matteson, but politics is old hat. Disillusioned with campaigns following the 2000 presidential election, he took to labor unions as a way to stay on the forefront of the national progressive movement.

Steve Matthews, Connecticut director of the union UNITE HERE!, who worked closely with Matteson for several years, praised his ability to connect with working people.

“It’s not compassion, exactly. It’s a sense of fighting for what’s fair,” Matthews said. “He really cared about getting what was best for [our members].”

Now, Matteson’s desire to “extend the fight to people who work really hard and play by the rules” has led him to New Haven’s City Hall, the final stop for issues of crime, violence and immigration in a sometimes-turbulent community. Matteson sees City Hall as one more arena in which to fight the same battle he has been fighting on campaigns and in labor unions his entire adult life.

“In his mind, it’s the same struggle, but a different avenue,” says Matthews. “He really is a very, very skilled political person, and politics is very important to unions.”

Matteson’s work ethic, exhibited during long nights at Hartford during debates over labor legislation, has already changed the tone of the office.

“He has extremely high expectations,” said Legislative Assistant Laoise King, who works under Matteson. “He expects things done right, and done right the first time.”

Matteson speaks with the voice of a man detached, as though another half of his mind was grinding away in the background, mulling over the morning’s education numbers or wondering where the ambulance outside his Church Street window is headed this time.

“No matter how much you want to tackle a specific issue, it’s realizing that it’s baby steps and getting it done,” Matteson says of governance. “If I could wave a magic wand and tackle any one issue, it would be violence.”

Hence the 18-hour days and the tie slipping from the collar beneath his stubbled neck.

“Sean believes very much in the issues his work is trying to advance,” says Rob Smuts, New Haven’s Chief Administrative Officer. “That was true at [the labor union] HERE and true here.”