The Sept. 14 primary produced many surprising results across the nation, but one of the more unlikely election outcomes occurred right here in Massachusetts: a successful write-in campaign.

No candidate was listed on the Republican ballot for attorney general, but nearly 30,000 voters wrote in Millbury lawyer James McKenna's name, giving Attorney General Martha Coakley an opponent for the Nov. 2 election.

A virtual unknown before he entered the race in late August, McKenna needed 10,000 votes to qualify for a ballot spot. On Tuesday, Secretary of State William Galvin announced that McKenna easily surpassed that threshold with 27,711 votes.

McKenna said he got a phone call last Tuesday from his campaign as he drove to his post-election party at the Cask'n Flagon in Boston, informing him that he was likely to make the ballot.

"It became pretty clear early on that things were really pretty good," McKenna said.

His campaign had calculated about how many votes from each town and city he'd need to reach 10,000.

"In Halifax we needed 19, we got 121," he said. "There was an extraordinary grassroots response to our candidacy, I can't even figure it out."

College of Communication professor John Carroll said that such a high total for a write-in candidate was unusual.

"The inclination going into the voting booth is not to write in somebody, the inclination is to vote for somebody who is there," he said.

McKenna, who also worked as a prosecutor for 10 years, has been campaigning for Coakley's office for fewer than two months. Up until July, he served as legal counsel for GOP auditor candidate Mary Connaughton, but said he was keeping an eye on the attorney general race.

"Many people were probably doing what I was doing, waiting for someone else to step up and do it," he said.

McKenna said the negativity of Coakley's race against Sen. Scott Brown was one deterrent.

"To step into that firestorm wasn't appealing to us," he said.

When he did decide to throw his hat in the ring in August, McKenna said the Republican establishment was grateful that someone was going for the nomination, but also saw a write-in effort as "impossible."

The state GOP party endorsed him two days after the primary.

"He's been running an impressive campaign," said party spokeswoman Tarah Donoghue. "People are fed up with business as usual and Martha Coakley deserves an opponent."

Donoghue said McKenna's campaign would have access to field offices and party staff, but would not comment on whether there would be any financial support.

On the issues, McKenna lists restoring public trust, fighting illegal immigration and taking on public corruption as his priorities, all things that he said Coakley has largely failed to do.

"When we have people on Beacon Hill who are stuffing money in their clothes and not prosecuting that ourselves, that is something that has to change," he said.

If McKenna does manage to unseat Coakley, he does plan to turn back the clock on the office in one respect: social media.

"The YouTube channel would be gone as of January," he said. "I would not be out there trying to be in front of every camera in the state, I'd be trying to get the job done."

But before he can start turning off the cameras, McKenna has to overcome the odds once more and pull of another Tuesday night shocker.

"I don't think Martha Coakley will be as easy prey as she was last time," Carroll said. "Everybody wants to pull a Scott Brown, but that was a combination of elements that came together that is not really reproducible.

"Does James McKenna have a camera-ready wife, does James McKenna have a daughter who was on American idol?"

McKenna has seemed to channel Brown in one respect: courting Tea Party voters without taking on the Tea Party label.

"I've been to a number of Tea Party events," McKenna said, although he added that his unsuccessful write-in opponent, Guy Cabone of Belmont, was the only self-described Tea Party candidate vying to be on the ballot.

"My thought on those folks is that they are doing the best to help their country."

Even if McKenna doesn't manage to capture political lightning in a bottle the way Brown did, many see his surprising success last Tuesday as evidence that the electoral landscape is changing.

"These are unusual political times," Carroll said. "The old expectations are being shattered one by one."

"It wasn't just our campaign, there was something more out there and that's the real news," McKenna said.