Standing in the way of a ninth term is challenger Bill Rubin, a Democrat who worked most recently as the vice chairman of the city's pension board and as a supervisor of elections for the City Commissioners Office.
Rubin, who also served as the treasurer for AFSCME District Council 33, said many people initially told him that running against O'Neill "was a fool's mission, that there wasn't really a chance to take down an incumbent."
"We've proven that's not the case," he said. "I'm out every day, knocking on doors, and people are telling me it's time for a change."
Change is in the air this season - six other council seats will be filled by new faces on Nov. 8 - but it's unclear whether that theme will be a factor in this race.
"People are angry as hell at incumbents on every level, but I'm certainly not writing off Councilman O'Neill," said Zack Stalberg, president of the Committee of Seventy, the civic watchdog group. "He's a cagey politician and a very tough competitor. He's a survivor."
Rubin, 44, has pitched himself as a Northeast Philly guy through and through - a high-school basketball coach, a mentor, a father whose kids attend local high schools. He's campaigned aggressively, claiming in a TV ad and during a debate last week that O'Neill still plans to enroll in the much-loathed Deferred Retirement Option Plan.
Rubin has also criticized O'Neill for the work he does as an attorney for the law firm Fox Rothschild.Being a councilman, he said, "should be a full-time job."
Last week, O'Neill, 61, said for the umpteenth time that he won't sign up for DROP. He filed paperwork in 2007 to find out what his DROP payment would have been but never went any further.
He also brushed off Rubin's barbs about his outside job, noting that being an attorney has helped him outfox lawyers and developers over zoning matters.
"The fact is," O'Neill said, "no council member or elected official has been as visible or accessible as I have been for the last 30 years."
Not everyone who has an interest in the race agrees.
"He's served eight terms, but he's not really distinguished himself," said John Featherman, who unsuccessfully ran for the Republican mayoral nomination this year as a member of the Loyal Opposition, the group that split from the Republican City Committee.
"The issue's going to be who gets more of their people out on Election Day."
Rubin is backed by a number of unions, including the powerful electricians union, Local 98, and the blue- and white-collar city workers. O'Neill has the support of the police and fire unions, among others.
Rubin has one unexpected backer: outgoing Councilman Frank Rizzo. The longtime Republican changed his affiliation to independent after O'Neill stripped him of his title of minority whip earlier this month - payback for Rizzo's decision to back a redistricting plan that O'Neill didn't support. Rizzo said last week that he donated $1,000 to Rubin's campaign.
Both candidates claim the support of 10th District residents.
"People are ready to make a change," Rubin said. "I tell people I'm running against Brian O'Neill, and they say, 'Who's that? I don't remember him ever knocking on my door.' "
O'Neill said his time in office speaks for itself.
"Look around. Does [the district] look good? Are we doing better than we were before I came into office? My opponent has called [the district] 'God's country.' The only constant in the last 32 years is me," O'Neill said.
"I wouldn't be running if it looked any other way."