If Mayor Nutter's personal aide has one rule to live by, it's this: "Don't mess with the playlist."

"There's some room for requests, but he drives the music choice," said Luke Butler, 28, who recently finished a two-year gig as Nutter's special assistant — a job that meant he spent more time with the mayor than anyone else in city government, traveling with him to meetings and events and listening to Nutter relive his former DJ days in the car.

Butler said that Nutter's top picks include old-school Philly groups like the Delfonics and the Stylistics, as well as current Philly stars the Roots. Some Top 40 creeps into the mix, too, Butler said, noting that Nutter introduced him to pop diva Adele before she became a household name.

Jordan Schwartz, who served as special assistant before Butler, agreed that Nutter controls the tunes.

"He owns the remote control in the car," said Schwartz, 33, now a deputy chief of staff. "There's a mix that is all different versions of 'I Believe I Can Fly.' There are more than I expected there to be."

Knowing the mayor's favorite tracks shows the kind of personal relationship the special assistant — a job known in political circles as the "body man" — has with the mayor. This 20-something aide, who sits at a desk right outside the door leading into Nutter's City Hall office, manages his schedule, travels with him to events, briefs him on policy issues and must stay on top of all kinds of little things — such as having a Sharpie on hand for signatures and business cards to hand out.

"I think the essence of the job is this is the person who will spend the most amount of time with me," Nutter said. "One, they need to be smart; two, they need to pick up things quickly, and, last, I gotta like the person."

As a result, this staffer knows the ins and outs of major city policies and plans, as well as all kinds of quirks about the big guy — like that yogurt is his breakfast of choice, that he's been an avid fan of "The Killing" on AMC, or that he chows down on Nodding Head's chili wings after a tough day.

"Yes, he's your boss and yes, it's a job, but there's this intense personal element to it that's unlike any other position," said Butler, who has just started as chief of staff for Alan Greenberger, the deputy mayor for economic development and planning. He has passed the torch to Lauren Walker.

Walker, 25, said that she's adjusting to the pace. "I always keep nuts in the car because I never know [when we'll eat]," she said. "Wherever the mayor is, I am right there."

The special assistant is by Nutter's side when he meets President Obama or rapper Jay-Z. But he or she also shoulders some of the toughest stuff about being mayor — from making difficult budget decisions to attending funerals of slain police officers.

Also, as a much younger staffer, the aide often also plays a role in keeping the mayor current.

"Facebook, Twitter, all of that has happened in the last five years," Nutter said. "They're much more in tune."

Butler and Schwartz have plenty of tales of life on the go with Nutter. There was the Thanksgiving car ride in 2010 during which Nutter stopped his police detail in Southwest Philly so that he could chastise a litterbug driving in front of him. Or the time Nutter stopped in Fairmount Park to quarterback a flag-football game with a group of kids.

Schwartz recalled a Saturday morning when he and Nutter drove past the former Impulse Nightclub at Broad Street and Germantown Avenue, Nutter's old stomping ground from his college days. Nutter knocked on the door and asked if he could look around.

Nutter said: "It was like the land that time forgot. Everything was the same. I went behind the booth. It was a little stroll down memory lane."

Nutter may have been the only mayor of a major city Thursday to issue a news release in response to the death of 1970s disco diva Donna Summer.

But perhaps Schwartz's favorite memory is when the 1990s rap star MC Hammer came to meet with Nutter. The mayor was running behind schedule and finally, Schwartz opened the door and said: "Mayor, it's Hammertime."

Sharing a sense of humor is key to success in this job. On Butler's last day as body man, Nutter staged a fake news conference and asked reporters to pose leading questions that suggested Butler was leaving the gig as a punishment. With a straight face, Nutter took questions about whether there was incriminating video, if Butler — who hails from the north of England — could be deported and whether Pippa Middleton, sister to Duchess Kate Middleton, was involved.

So how is Walker adjusting to the job? A couple of weeks in, she says she likes the work so far. But she, too, has noticed the mayor's tight control over the music in the car.

"His MP3 player is the most important thing to him outside [of being mayor]," Walker joked.

She said there has been a lot of Jay-Z lately, given the news that the rapper will host a music festival in Philadelphia. But, she added: "Last week, it was Barbra Streisand." n

Contact Catherine Lucey at 215-854-4172, luceyc@phillynews.com or follow @phillyclout on Twitter. Read her blog "PhillyClout" at www.phillyclout.com.