He'd agreed to run under one condition: He would not, under any circumstances, miss any of his daughter's high-school basketball games.
So it was that on the Friday before Election Day, Dominick Ianno, then the executive director of the Massachusetts Republican Party, found himself shuttling then-state Rep. Brown between Boston and two different suburbs so Brown could wedge in a basketball game between two final campaign debates.
With rush-hour traffic, he would barely make the second debate on time. But he wouldn't leave Ayla's game even a minute early.
"Making time for his daughter's games was a no-brainer. But I had more respect that it was his only caveat," Ianno said.
Brown, a 50-year-old lawyer and National Guardsman, Tuesday pulled off one of the great upsets in political history -- grabbing Ted Kennedy's old Senate seat in the Democratic bastion of Massachusetts, and handing Republicans a critical 41st Senate vote.
He did it with the same style he displayed by taking that state Senate seat in 2004, and a state House seat six years before that: With a relentless energy and blue-collar sensibility that belied his decidedly upper-middle class lifestyle.
Today, at his first post-election press conference, the man who ran on a promise to block President Obama's health care bill vowed to be an independent voice -- a "Scott Brown Republican," he said, echoing a common campaign refrain.
"I've already made it very, very clear that I'm not beholden to anybody," Brown said. "I've been asked many times what kind of Republican I would be, and I really didn't know how to answer that. So I said I'm going to be a Scott Brown Republican… maybe there's a new breed of Republican coming to Washington."
Prominent GOP officials, thrilled with the upset victory, proclaimed Brown to be something of a template for the candidacies they hope to run in 2010.
"No one believed it was possible -- especially in the bluest of blue states," National Republican Senatorial Committee Chairman John Cornyn, R-Texas, wrote in a memo today. "But the political naysayers who discounted Brown's candidacy and anointed Democrat Martha Coakley after she won her party's nomination miscalculated one important factor: Voters' utter dissatisfaction with the status quo."
Before catapulting himself to national attention over the race's final two weeks, Brown was perhaps best known for a few pieces of tabloid-ready trivia.
He posed nude for Cosmopolitan as a law student in 1982; his basketball-playing daughter Ayla Brown was a semi-finalist singer on "American Idol"; he's married to a TV news reporter, Gail Huff, who works at WCVB-TV, ABC's Boston affiliate.
Though he shares a home state with a once and possibly future presidential contender, former Gov. Mitt Romney, R-Mass., his rise more closely resembles that of Sarah Palin, an aw-shucks populist who tapped into voter anger and frustration aimed at Washington.
There are shades as well of Barack Obama's meteoric rise: Obama also went straight from the state Senate to the U.S. Senate, and was catapulted to national prominence in Boston, at the 2004 Democratic National Convention.
Brown grew up in Wakefield, Mass., and was a star athlete growing up, as well as something of a self-professed troublemaker. He first ran for the state legislature in 1998 after a stint in local government in Wrentham, Mass.
He had an independent streak from start in politics. Ianno recalls that Brown was an early supporter of Sen. John McCain's 2000 presidential campaign, when most of the state GOP establishment was backing George W. Bush.
He's a social conservative by Massachusetts standards, though not by national ones: He's a strong opponent of same-sex marriage, but he's said he doesn't favor overturning the Roe v. Wade decision that legalized abortion.
He was a reliable vote against tax increases in the Democrat-dominated legislature. He supported the Clean Election Law, a controversial public campaign-financing system that was ultimately repealed after being approved by Massachusetts voters.
Brown built his campaign around his opposition to the president's health care plans, though he supported Romney's successful effort to establish virtually universal health coverage in the Bay State.
At the State House, Brown developed a reputation less as a legislator than as a connection-builder, filling his Rolodex with contacts who would come in handy down the road. As a junior lawmaker, colleagues knew of his ambition -- and his drive.
"Scott was someone, by virtue of nature, was competitive. He certainly saw some desire to move up, move on, with an opportunity that presented itself," said state Rep. Bradley H. Jones Jr., R-Mass., the Massachusetts House minority leader.
After Kennedy's death, Brown had a relatively easy shot at the GOP Senate nomination. Big Republican names, such as Romney, former White House chief of staff Andy Card, and former governors Paul Cellucci and Jane Swift, took a pass. Few gave him any shot of winning against the then-popular Democratic attorney general, Martha Coakley.
In a tight timeframe, Brown worked the state in a weathered GM truck, boasting that he had 200,000 miles on it, and that he would gladly see the odometer roll up for a trip to Washington.
He used social media networks and online advertisements to a degree that only Democrats -- including Obama -- had truly used successfully in the past.
By two weeks before the election, he had showed enough progress in some polls that national Republicans started paying attention. By the end of the race, he was raising a virtually unprecedented $1 million a day, money he literally couldn't spend fast enough. He closed out with a campaign war chest of some $4 million, according to campaign aides.
"He ran a tremendous campaign that connected with the pieces that people cared about," Jones said. "And [Coakley] ran a horrible campaign. She ran a campaign -- some would say of arrogance, some might say of entitlement."
Brown's eagerness to meet as many voters as possible put him in stark contrast with Coakley, who at one point famously mocked Brown's decision to shake hands outside of Fenway Park "in the cold."
Last night, when President Obama called to congratulate him on his victory, Brown said he offered to show him his truck down in Washington. If some Republicans have their way, that truck could become more famous yet.
ABC's Devin Dwyer and John Berman contributed to this report.