Gov. Ned Lamont declared victory late Tuesday night as Republican challenger Bob Stefanowski did not concede defeat in a tight race.

In a rematch of their 2018 race, Fox News declared Lamont the winner around 9:30 p.m. Tuesday but Lamont did not speak until about two hours later to Democrats who gathered for an election night party in Hartford.

The votes were still being counted in the high-profile election that showed a dichotomy between high-turnout suburbs like Simsbury and lower-turnout cities like Hartford. Democrats expressed confidence that Lamont would win, while Stefanowski sent an email shortly after 7 p.m. that urged supporters to get to the polls during the final hour because “this is a winnable race.’'

By 11:20 p.m., Stefanowski had not yet conceded.

The two multimillionaire former business executives poured portions of their fortunes into an increasingly bitter race that led to sharp disagreements on virtually every issue — taxes, state spending, inflation, crime, abortion, and the use of the state’s rainy day fund.

Between the candidates and outside groups, more than $43 million was spent on the governor’s race — with the number still rising as automatic robocalls continued on election day to get voters to the polls The race turned personal as the candidates questioned each other’s version of the facts that were cited in debates, commercials and on the campaign trail.

But Lamont led in the public polls from start to finish as he outspent his rival, who has never held public office. Stefanowski said that his internal polls showed the race within the margin of error, but he never claimed to be in the lead despite spending more than $10 million of his own money.

As the great grandson of the financial partner of famed financier J.P. Morgan, Lamont, 68, has been building wealth for decades that allowed him to earn $54 million in 2021 — mostly from capital gains in a year in which the stock market boomed.

Turnout was high Tuesday in some towns across the state as most adults were keenly aware of election day due to the months-long blizzard of television commercials and national news about the battle for control of the U.S. House of Representatives and U.S. Senate. The midterm elections were crucial nationwide as Republicans sought to capitalize on President Joe Biden’s sluggish poll ratings.

The turnout in some Connecticut towns like Simsbury, Enfield, and Ellington was strong, but Democratic operatives were concerned that turnout was much weaker in places like Hartford. Danbury remained solid, while Waterbury and New Haven had lower than expected turnout as of mid-afternoon, Democrats said. Turnout was higher in the suburbs of the Farmington Valley, but the one-time Republican stronghold has been turning Democrat in recent years.

Statewide, turnout was expected beyond the 65% level of the 2018 governor’s race, based on an estimated 35% turnout as of 2:30 p.m.

Former state Democratic Party chairman John Droney, who has been closely watching campaigns for decades, said some voters had already made up their minds in favor of Lamont during the pandemic that swept across the state and the nation.

“I thought that he won the election the way he handled the COVID-19 problems earlier,’' Droney said in an interview. “Everybody didn’t really know who he was, and they saw him as a pretty sincere, honest guy, trying to do his very best for the people, and they liked him. That has never been overcome by his opponent. He won the election when he handled the COVID-19 pandemic like a real pro. There wasn’t much that Stefanowski could do about it.’'

Lamont’s approval ratings skyrocketed in May 2020 after nearly two months of daily televised briefings and crisis decisions on the pandemic. At that point, 78% of those polled approved of Lamont’s handling of the pandemic, while only 17% disapproved, according to the Quinnipiac University poll. Some critics sharply derided Lamont as “King Ned’' for making unilateral decisions without votes on various issues by the state legislature, but the polls showed that many voters approved of his actions.

“I don’t think Stefanowski is a bad man or that he’s not a sincere guy,’' Droney said. “He just can’t beat Lamont. It’s that simple. ... He had the chance to run for governor, and it was a lot of fun - but wrong person, wrong time.’'

Droney did not attribute Lamont’s victory to high campaign spending, noting that Republican Linda McMahon spent $50 million in each of two races in 2010 and 2012 - and lost both times.

One of Stefanowski’s biggest mistakes, insiders said, was parting ways with Liz Kurantowicz, a seasoned campaign operative with experience in multiple races. After leaving Stefanowski’s campaign, Kurantowicz went on to devote all her time to Republican George Logan’s battle against U.S. Rep. Jahana Hayes of Wolcott as Logan closed the gap against the two-term incumbent.

Some insiders said another mistake was Stefanowski’s continued criticisms of venture capitalist Annie Lamont as Democrats said that attacking the candidate’s wife was out of bounds. At the same time, the attacks only solidified the resolve of the Lamont campaign and ensured that big spending would be unleashed to defeat the Republican.

Stefanowski campaigned hard until the end — broadcasting commercials that were still running Monday night.

“We can do better, Connecticut,’' Stefanowski said in a 30-second spot. “You want change, Connecticut? Change governors.’'

He also continued blasting Lamont and Independent Party candidate Rob Hotaling of Cheshire in his final press conference.

“They’re both anti-police,’' Stefanowski said of his rivals. “They’re both soft on crime. They’re both supporters of Dan Malloy.’'

Before the polls closed, Stefanowski spoke to reporters Tuesday at the watch party at the Trumbull Marriott, where a ballroom was decorated with red, white, and blue balloons.

“We’re seeing a good turnout, and we’re excited about it,” Stefanowski said.

He added, “Connecticut needs a change in direction” after 40 years of largely Democratic rule in the state legislature.

Compared to the 2018 race, Stefanowski said he tried to be more relaxed and show people he’s “just a regular guy.’' Noting that he grew up in a three-family house off Dixwell Avenue in New Haven, Stefanowski said he knows what it’s like to “struggle, drive a used car.”

Despite being a multimillionaire who earned as much as $15 million annually recently with a large consulting client in Saudi Arabia, Stefanowski says he still buys used cars because his father taught him about striking a bargain.

Democratic state chairwoman Nancy DiNardo said Lamont’s personality proved to be an asset on the campaign trail and in the state’s highest office.

“Right from the beginning, what you see is he is not a politician,’' DiNardo said at the Democratic election night party. “He really is a businessman. He’s never looked at Democrats and Republicans. He meets with everyone. He gets along with people. I think that has made a difference for him. ... That’s just Ned’s personality.’'

When Stefanowski was far less known in 2018, he lost to Lamont by three percentage points. He won the 2nd and 5th Congressional districts in 2018 — two large districts where Republicans have sometimes scored well. He lost Waterbury in 2018, but said he planned to win it this year.

The big difference for Lamont comes in the cities, particularly Democrat-heavy New Haven. Under the supervision of town chairman Vinnie Mauro, New Haven is a well-oiled machine that traditionally churns out Democratic votes and delivers huge majorities for gubernatorial candidates. New Haven helped turn the tide for Dan Malloy in both 2010 and 2014, as well as Lamont in 2018.

Unlike many Republicans nationally, Stefanowski said he would accept the outcome this year and said the election had not been stolen from President Donald J. Trump.

“I’ll accept the results,’' Stefanowski told reporters Monday outside the state Capitol in Hartford. “It wasn’t stolen. Joe Biden is the rightfully elected president.’'

While Democrats repeatedly tried to paint Stefanowski as extreme throughout the campaign, he rejected that notion and described the Republican gubernatorial ticket as “very middle-of-the-road socially.’'

During the campaign, longtime Quinnipiac University political science professor Scott McLean said the cities would be crucial for Lamont.

“If not for the turnout in the cities for Lamont four years ago, Stefanowski would have won,” McLean said. “Lamont knows he needs the Connecticut cities to vote for him strongly.”

Stefanowski had been trying to break a 15-year losing streak by Republicans in major races in Connecticut. In 2006, then-Gov. M. Jodi Rell and then-U.S. Rep. Chris Shays of Bridgeport both won re-election. But Shays lost in the Democratic wave that swept in Barack Obama as president in 2008, and no Connecticut Republican had won a seat for Congress, governor or other statewide office since then.

But Stefanowski said he worked hard to make a dent in the cities.

He said that he and his wife, Amy, had visited Bridgeport 100 times during the past four years.

“That’s not an exaggeration,’' Stefanowski said.

Courant staff writer Pam McLoughlin contributed to this report.