"Congratulations to Jim on a hard fought victory," Love said. "It was a close race, but ultimately the voters of Utah have spoken."
Matheson addressed supporters briefly, thanking them for their support and saying he looked forward to serving them.
"I think this race went exactly as I assumed it would," Matheson said, saying the differences on education and his bipartisan approach, and meticulous ground game made the difference. "Never had doubts."
The war between Matheson and Love was epic, drawing unprecedented national attention and money for a Utah contest.
State and national Republicans held nothing back, pouring more than $5 million into the effort to unseat Matheson, whose presence as a Democrat holding a congressional seat in the most Republican state in America tormented the GOP.
Matheson and his backers countered with more than $5 million of their own spending, rallying to protect the incumbent. The resulting spending binge saturated airwaves and shattered records for spending on a Utah congressional race.
Had she won, Love would have been the first black Republican woman in Congress and the first black member from Utah.
Five times Matheson has survived bids by Republicans to knock him out of office. The closest brush with defeat was his first re-election bid in 2002, when he survived by about 2,000 votes.
"I think at the end of the day I'm just different from most people in politics. I just do the right thing," he said. "That carries the day with most voters, regardless of party."
Damon Cann, a political science professor at Utah State University, said Matheson probably ran a better campaign than Love, but Matheson was fighting against a tough new 4th District which leaned heavily toward the Republican and broad support for Republican presidential candidate Mitt Romney.
The presidential contest loomed large in the 4th District battle, with Love wrapping her candidacy in the Mitt Romney mystique, seeking a boost from an immensely popular candidate with Utah ties, while painting Matheson as a Barack Obama sympathizer.
"In an election that is this close, even if having Romney on the ballot mobilizing more Republicans or having Obama in the back of people's minds … if that affects one or two percent, in an election as close as this one, even that can make a difference," Cann said.
Matheson painted Love as a radical conservative who would slash safety net programs for the poor, public safety grants, education funding and subsidized college loans that she used to attend school.
Love had proposed deep cuts to the federal budget when she was vying for the Republican nomination, but backed away from them later, saying they were merely suggestions and essential programs could be picked up by the states.
It was the first time in years that Matheson has not easily outspent his opponents, as Love tapped the support of major Republican leaders including vice presidential nominee Paul Ryan, House Speaker John Boehner, former Secretary of State Condoleezza Rice and Arizona Sen. John McCain who raised money for Love in Utah.
She also gained national attention by landing an evening speaking slot at the Republican National Convention, exposure that raked in hundreds of thousands of dollars to her campaign.