Mark J. Grisanti won re-election Tuesday to the State Senate’s 60th District seat he has held for two years, putting a decisive end to a campaign that was long, expensive and more heated than many expected.

Grisanti, a Republican, scored a comfortable win, tallying 50 percent of the vote in the all-Erie County district, with almost 91 percent of districts reporting.

The district stretches from Tonawanda and Buffalo to the Southtowns, including the towns of Orchard Park, Hamburg, Evans and Brant.

Michael L. Amodeo, the Democratic challenger to the one-term incumbent, received 36 percent of the vote.

Charles M. Swanick, a former county legislator who was defeated by Amodeo in a primary for the Democratic line, stayed in the race on the Conservative line and tallied 12 percent of the vote, the partial tabulation showed.

Grisanti, 48, a North Buffalo resident who was first elected to the Senate in 2010, celebrated the results in an after-polling party at SoHo Burger Bar in the Chippewa district downtown.

Grisanti attributed his victory to what he called Western New York voters’ ability to cross party lines to support candidates that they see as working for the betterment of the region.

“For the past three years, I have not only worked across the aisle for the benefit of Western New York, for my district, and the benefit of New York State as a whole, and I think you know that, the dysfunction that we had in 2009-2010 is gone,” Grisanti told the enthusiastic crowds in the downtown restaurant.

“Working across the aisle is key – and what we saw tonight, by working across the aisle, was voters crossing [party] lines.”

Amodeo, 33, is an attorney who lives in Lake View and has never held elected office.

“I have the resolve to get back on the horse and make sure Western New York is a better place,” said Amodeo, who told the crowd in Democratic election night headquarters that he did not regret his decision to run. Amodeo said he planned to stay involved in politics.

Swanick, 63, a Town of Tonawanda resident, did not return a call from The Buffalo News.

In purely logistical terms, analysts of the race said, the victory was not one that Grisanti should have been able to pull off – at least not handily.

The 60th State Senate District, which was recently redrawn, offers a sizable advantage to Democratic candidates, with Democratic enrollment totaling more than 2 to 1 over registered Republicans.

That made Grisanti’s race, on paper, a tougher one than it proved to be – especially factoring in the personal issues and political storms the incumbent has weathered in the past two years, ranging from a fistfight in a local casino to his controversial vote on legalizing same-sex marriage.

“After that business in the casino and the new district, you sort of would have thought that Grisanti would have had a lot more trouble than he ended up having,” said Michael V. Haselswerdt, a professor of political science at Canisius College, referring to a well-publicized scuffle that Grisanti got into at the Seneca Niagara Casino last winter.

Then there was the issue of Grisanti’s vote last year to legalize same-sex marriage – a vote that Grisanti said he was hearing about repeatedly on doorsteps while campaigning over the past few months.

“When I went door to door in the primary, the first thing people said to me was, ‘You switched your vote on marriage equality,’ ” Grisanti told the Editorial Board of The News in October. “I felt I voted my conscience.”

Grisanti may have counteracted some of those questions among voters with his strong support for the tax cap – a pet project of Gov. Andrew M. Cuomo – and other measures that Western New Yorkers might have felt benefited their pocketbooks.

Grisanti’s opponents in the race, which also included Gregory L. Davis on the Working Families Party line, may not have made enough of a “compelling case for getting rid of him,” said Haselswerdt.

What else made the difference, in the end, for the incumbent?

Clearly, observers said, money played a large role.

Grisanti, an attorney who practices out of a West Side law firm operated by his family for three generations, outspent his rivals by staggering sums – especially in recent weeks.

Grisanti was spending as much as $20,000 per day on the campaign – more than $400,000 overall – in the final few weeks of the contest, much of it on TV ads.

Grisanti drew on two sources of campaign cash not accessible to his opponents: donations from constituents who knew and supported him from his work in the district over the past two years, and contributions from groups and individuals associated with the gay rights movement in the state and around the country. Many of those donors had lauded the Republican newcomer to the Senate when he changed his former stance on same-sex marriage and voted for the marriage legalization.

That sort of funding far outweighed the money Amodeo and Swanick had available to find their campaigns.

News Staff Reporter Harold McNeil contributed to this report.