The rarefied air of Harvard Law School was full of possibilities for Tim Kaine when he arrived in 1979. But, within a few months, the young Midwesterner was searching for answers that could not be found in one of the nation's elite intellectual hotbeds.

"I really wasn't sure in the middle of my first year," Kaine said, recalling the uncertainty he felt as a 21-year-old. "What do I want to do? What am I really committed to? What values are important?"

The answers came to him over the next year, when he put law school on hold to work with Roman Catholic missionaries in Honduras. Kaine had briefly visited the country while attending a Catholic high school and had hoped to return. His second visit would be a life-changing experience.

Kaine ran a vocational school, teaching carpentry and welding to teens in the Western Hemisphere's second-poorest country. The school's founder, American missionary Jim O'Leary, became a mentor who helped Kaine find the direction he lacked at Harvard.

"It was about the good Samaritan principle," Kaine said. "What Jim taught me, what that year taught me, is to measure your life by the difference you make in other people's lives -- not by what you put in your own pocket."

Kaine returned to law school with a new focus. He decided to pour his talent and energy into public service, eschewing lucrative opportunities that many of his peers would pursue.

"The important thing was he was committed to doing something in service to others," said Scott Brown, who met Kaine in law school and remains a close friend. "I think he had those strong beliefs before he went, but wasn't sure he wanted to make a life commitment."

The decision led Kaine to the legal career he carved out in Richmond and to a political career that has him running as the Democratic nominee for governor in 2005.

"I just came back very focused on wanting to use my legal career to help people out," Kaine said.

Kaine, 47, tells the story of his year in Honduras to nearly every audience he meets on the campaign trail. He explains that his experience in Central America taught him the virtue of putting "faith in action" and exposed him to a standard of public service he has measured himself against ever since.

"My career in public service was really shaped by that mission," he said while riding between stops on a July campaign swing through the New River Valley.

Kaine grew up in the Kansas City suburb of Overland Park, Kan., the oldest of Al and Kathleen Kaine's three sons. His father ran a small iron welding shop in the stockyards of Kansas City, where all three boys would work during their high school years.

Kaine's parents, who still live in Kansas, said their oldest son was a gregarious kid with a good set of friends. Kaine's mother said he was "an active debater" in high school, but politics was about the last thing on the youngster's mind. To Kaine, politics seemed no more real to him than the baseball games and movies he watched on television.

"My family is like most families," Kaine said. "We never had our names in any newspaper, and nobody we knew ever did, either."

In fact, Kathleen Kaine said in September, "some of our friends are just now realizing that Tim is running for governor."

Kaine's interest in the law was sparked by books he read as a youth such as Harper Lee's "To Kill a Mockingbird" and Richard Kluger's "Simple Justice," a history of the landmark Brown v. Board of Education case. He headed east to Harvard after graduating in just three years from the University of Missouri.

His decision to take a year off for his mission to Honduras put Kaine on a new graduation schedule when he returned to Harvard. And it put him in the same class with the woman he would marry -- a Roanoke native named Anne Holton whose passion for public service rivaled his.

"He naturally had good perspective about law school and life," said Holton, the daughter of former Virginia Gov. Linwood Holton. "I was faking it and trying to impress him."

Their career paths led them to Richmond, where Holton became a Legal Aid lawyer and Kaine signed on with a small law firm. They stayed in the state capital, where Kaine would move on to a larger law firm and Holton would become a juvenile and domestic relations judge. The couple have three children.

"You could tell this was a city where you could sink your teeth in and get involved," said Holton, who can't participate in her husband's political activities because of judicial ethics rules.

Kaine did legal work for local governments and small businesses, and loved opportunities to handle civil rights matters. His first client was a black woman whose apartment rental application had been rejected because of her race. After Kaine won a settlement for her, he found more housing discrimination cases being referred to him.

One referral came from the American Civil Liberties Union, which asked Kaine to handle a discrimination complaint for a state prison warden and his wife. Ellis and Virginia Wright made an offer on a house in Emporia, only to see it sold to a group of white neighbors who bought it for less than the couple's original offer. Kaine won a settlement for the couple, a victory that underscored his belief that "dignified housing is something that is very much a part of who we are."

"There are a whole lot of cases where it doesn't matter, in the grand scheme of things, which side wins a contract case," Kaine said. "But in civil rights cases, it does matter. I really enjoyed working on those."

Politics began pulling at Kaine as he became more involved in his community. Disturbed by Richmond's racial divisions, violent crime and struggling schools, he decided in 1993 to run for the city council. At the time, he remembered an admonishment he often heard from his father-in-law, Virginia's first Republican governor of the 20th century.

"I'm always hearing Lin Holton talk about, 'Good people with good educations should think about getting into public service,' " Kaine said.

But local politics were not what Linwood Holton had in mind, as Kaine discovered when he informed his father-in-law of his plans.

"My dad thought he was crazy to run for local office," Anne Holton said. "Why would anybody want to do that and have people call you up at 4 in the morning to say there's a dead dog in the street?"

Kaine served on the council for four years before his fellow members elected him mayor in 1998. Controversies dogged some of Kaine's fellow council members during his tenure, but he tried to work through the distractions to build consensus behind efforts to reduce crime, build new schools and improve the city's business climate.

"I tell people I haven't broken a sweat once since being mayor," Kaine said with a chuckle. "It was grueling and hard and comical -- it was like a Fellini movie at times. And yet, it was also extremely satisfying."

Republican gubernatorial candidate Jerry Kilgore has called Kaine "a mediocre mayor," placing particular emphasis on Richmond's struggling schools. But Kaine points out that the city made progress in education and other critical areas during his tenure in city government.

"I think what gets lost is where we were in 1994 when we all went on the council and how far we've come," said Viola Baskerville, who served on the council with Kaine for three years before getting elected to the House of Delegates.

Kaine takes particular pride in the city's efforts to renovate the old Maggie L. Walker High School, a decaying facility that had been vandalized and occupied by homeless people when Kaine first joined the council. Kaine led the push to renovate the building, which now houses a regional Governor's School for gifted and talented students.

Baskerville, who also pushed hard for the renovation, said school construction efforts launched during Kaine's tenure improved neighborhoods and made the city more competitive in recruiting businesses.

Education became the driving issue of Kaine's successful 2001 campaign for lieutenant governor. Kaine joined the race after presumed front-runner Emily Couric, a state senator from Charlottesville, bowed out because of an illness that would take her life. Kaine mounted what he described as a single-issue campaign, calling for the state to fully fund its share of public school costs.

Kaine said he had misgivings about running in 2001. If he won, he could expect to become the Democrats' instant favorite for the 2005 gubernatorial nomination. A four-year commitment could become an eight-year commitment and cost him time with his wife and children. But, with his family's support and a spark that was lit in Central America more than 20 years earlier, he pressed on.

"We're happy," Kaine said, flashing a satisfied smile. "We love what we're doing. I don't know many people who are happier than me. I love what I'm doing. I love the things I've chosen to do."