Sullivan had been the biggest question mark. Unlike Winslow and Gomez, the Abington resident had relied solely on volunteer signature gatherers. Winslow and Gomez had relied on a mix of volunteer and paid gatherers.
Wednesday was the deadline for dropping signatures off at local city and town clerks to be certified. The signatures must be collected later and delivered to Secretary of State William Galvin's office before a candidate's name can officially be added to the ballot.
Sullivan said he was excited to submit so many signatures after launching the drive just 12 days ago. He said the ability to gather so many signatures so quickly shows he has a groundswell of support.
Sullivan described himself as fiscally conservative and said Congress and the White House share the blame for the current fiscal stalemate.
"I think there's tremendous common ground if people would apply some common sense," he said, speaking to reporters after dropping off a batch of signatures Wednesday morning at Abington Town Hall.
Sullivan, who likely has the strongest name recognition among the three Republican candidates, said he does not see himself as the front-runner, adding that "it's been a long time since I've gone out and campaigned."
He acknowledged that as a Republican, he faces an uphill battle in a largely Democratic state. He said before making his decision to run, he spoke to former U.S. Sen. Scott Brown, who encouraged him.