Michael Nutter, a reformist candidate who was given no shot of winning just a month ago, captured the Democratic mayoral nomination Tuesday and is all but certain to become the next mayor of Philadelphia.

Nutter won by a resounding margin, defeating businessman Tom Knox, who spent nearly $10 million of his own money, as well as U.S. Reps. Bob Brady and Chaka Fattah, and State Rep. Dwight Evans.

The former city councilman, a determined foe of Mayor Street's in recent years, prevailed in a primary that marked the first time in decades that voting did not follow clear racial lines.

And Nutter could take satisfaction in knowing that he won by more than twice the margin Street registered in winning a similar five-way primary eight years ago.

“We had a pretty decent couple of weeks,” Nutter, with his wife and daughter at his side, told a delighted overflow crowd of more than 500 people in the ballroom of the Radisson Plaza-Warwick Hotel. “We had a really good day.”

He thanked his four rivals, all of whom pledged support for him last night. He said he would need their help down the road.

“We have to lower the crime rate and make this city safe,” Nutter said. “This is our time and this is our place. We can do better as a city, we will do better as a city.”

Knox, in conceding, took solace in noting that the contest had not been racially divisive and that voters across the city had embraced the desire for something new, even if they had not embraced him.

“The fact that the two top finishers in the race were both reform candidates is a testament to the people of Philadelphia and the fact that they want real and meaningful change,” Knox told his supporters.

He added later: “It doesn’t matter how much money I spent. … I always said, if I didn’t win, it should be Michael Nutter. Thank God it’s not Bob Brady.”

That feeling was mutual.

“It just goes to show — and I feel really good about the fact — that we are not for sale,” Brady, the city Democratic chairman, told friends and supporters who roared approval. “I’ve been fighting millionaires all my life, and I fought one today.”

Fattah congratulated his rivals on the campaigns they waged and said he was proud to have “stood for principles first and foremost,” highlighting the need to address long-term poverty in the city.

Evans, too, was gracious in defeat, consoling his supporters by saying, “Something happened today which was not life or death. It was an election.” He lamented that issues seemed to be overshadowed by the horse race in the final weeks.

Voting was slowed in many areas by the size and complexity of the ballot. Some polls stayed open after the 8 p.m. closing time to allow those in line to cast their votes. Turnout appeared to be just under 300,000 Democratic voters, about the same as the last contested mayoral primary, eight years ago.

Nutter will be a prohibitive favorite in the November election, considering the Democrats’ 5-1 registration advantage in the city and the fact that a Democrat has occupied the second floor of City Hall since 1952. Al Taubenberger won the Republican nomination unopposed.

The indications that the voting was less racial in nature than in past elections came from the ward-by-ward numbers and from voters interviewed leaving the polls yesterday. They said they were concerned primarily with the candidates’ leadership skills, and how they would deal with crime and other issues.

June Schroeder, 72, a white retired businesswoman from the Spring Garden section, said Nutter was her favorite because he “seems to be a person who isn’t angry. No matter what’s thrown at him, he seems to be able to deal with it. He seems to be a clear thinker. And he’s not full of razzmatazz.”

Bettina Bannister, 64, who is black and from Mount Airy, said she voted for Knox. “The African Americans are tired of the African Americans” in office, she said. “You have nothing to look up to with the scandals. We just want something different.”

One factor that seemed to figure in many voters’ decisions was the amount of money Knox spent on the campaign.

Some voters said they resented his spending and did not want him to be able to buy the election. Others liked the idea that he would be beholden to no one as mayor.

From the outset, the Democratic race to succeed Street was a fascinating and unpredictable affair. At one time or another, four of the five major Democratic candidates were seen as the possible winner, the exception being Evans.

The first front-runner was Fattah, the seven-term congressman known for the strength of his political organization. From the moment he expressed interest in the race a year ago, he was widely considered the most likely survivor.

Brady was seen as a possible victor, as well, once he started making mayoral noises — thanks to his role as chairman and the theory that he might be able to use his vaunted negotiating skills to maneuver some candidates out of the race.

Knox, the millionaire insurance executive who served as a deputy to Ed Rendell when he was mayor, moved into the lead two months ago on the strength of a TV advertising barrage funded by his wealth.

And Nutter, who had been written off by most politicians for months, surged into the lead in the final 10 days, thanks to his reformist message and his own late television blitz.

Evans, despite fulsome praise from Gov. Rendell, never seemed to find his footing. In polls, Democrats gave him favorable ratings but not their votes.

For the most part, the campaign was a civil and substantive affair, with the candidates releasing detailed positions on crime, education, taxes, ethics and other issues, and traveling around the city for one forum after another.

But in the final weeks, with a clear pecking order taking shape, the tone grew nastier.

Once Knox was in the lead, Brady picked apart his business record, accusing him of having at times acted against the interests of working people.

When Nutter surged, Fattah sniped at him, famously accusing the former councilman in a debate of having “to remind himself that he’s an African American.”

Independent committees known as “527”s ran ads attacking Knox on his business practices and Nutter on his plan to have police stop and frisk individuals suspected of carrying illegal guns.

And last weekend, an unsigned, pro-Knox flyer left on cars in church parking lots accused Nutter, a Baptist, of having abandoned the Catholic Church for political reasons and Brady, a Catholic, of not going to church at all.

Last night, Nutter said he was delighted the race was over.

So, too, was Linda Knox, whose husband spent what amounted to $135 for each vote he received. After hearing her husband say he probably would not run for office again, she interjected a firm “No.”

The microphones turned to her: “I said no!”

Asked whether the political bug had bitten her husband, she replied, “I’m going to bite him if he runs again,” saying she thought there were charitable causes that could use the next $10 million.

Contact senior writer Larry Eichel at 215-854-2415 or leichel@phillynews.com.

Contributing to this article were Inquirer staff writers Marcia Gelbart, Jennifer Lin, Michael Matza, Craig R. McCoy, Robert Moran, Andrew Maykuth and Michael Vitez.