By Richard Cowan

PADUCAH, Ky, Sept 21 (Reuters) - Mitch McConnell is hardly a lovable guy. The Republican leader in the U.S. Senate has a dour public persona and many of his constituents don't view him as a "real Kentuckian," according to a Reuters/Ipsos poll that underscores what his election campaign already knows - McConnell has an image problem.

While other politicians might be deterred by polls showing how unpopular they are in their home state, McConnell has risen to the challenge as he seeks a sixth term in what is perhaps his toughest re-election battle in a 30-year Senate career.

Relying on broad financial support from corporations and donors, he has launched a series of withering attack ads on Democratic challenger Alison Lundergan Grimes, linking her with an even more unpopular President Barack Obama. At the same time, McConnell has used social media to soften his image and make light of his blandness.

The two-pronged strategy marks a change in emphasis for McConnell. While he has always been aggressive on the campaign trail, in the past he has overcome his charisma deficit by touting his ability to bring government-spending projects home to Kentucky. But the conservative anti-spending Tea Party turned that into a negative for Republicans.

If McConnell and fellow Republicans succeed in seizing control of the Senate from Democrats on Nov. 4, he would become Senate majority leader, a powerful position from which he could derail what remains of Obama's second-term legislative agenda.

"He doesn't have a deep reservoir of public regard that can keep getting him re-elected. He has to go out and fight to get re-elected," said Al Cross, a University of Kentucky journalism professor who spent 16 years as a political writer for Louisville's Courier-Journal newspaper.

A recent Reuters/Ipsos poll found more than half of the state's voters view McConnell unfavorably, one-third describe him as an arrogant Washington insider and only 11 percent chose the words "real Kentuckian" to describe him.

McConnell, born in Alabama, has spent most of his life living in Kentucky. He attended high school there and graduated from the University of Louisville and the University of Kentucky's law school. But many Kentucky voters think "'he's no longer one of us, he's one of the DC bubble types,'" said Ipsos pollster Julia Clark.

The poll still gave McConnell a slight 4-point edge over Grimes among likely voters, 46 percent to 42 percent.

McConnell told Reuters his tough reelection race had little to do with his popularity and more to do with his position as a leader in the Senate.

"When you accept the responsibility to be the leader of your party you get targeted by the other side and it just sort of goes with the turf," he said.

'THAT WAS DRAMATIC'

McConnell's lack of charisma was evident at a recent campaign gathering in rural western Kentucky, where he answered the small crowd's welcoming applause with a clinical, 11-minute review of his achievements punctuated by references to a 10-year-old legislative "conference report," a "section 179" tax provision and "the $5 million per person estate tax exemption indexed for inflation in permanent law."

It was interrupted when a reporter accidentally knocked over a metal fuel can, setting off a loud clang.

"That was dramatic," McConnell said undramatically.

Still, McConnell has a knack for winning close races. In five previous Senate bids, he has earned more than 55 percent of the vote only once. In his last race, in 2008, he won with 53 percent.

Corporations and millionaires around the country have poured millions into a race against Grimes that eventually could rank as one of the most expensive ever.

By the end of June, McConnell had more than doubled the amount raised by Grimes, Kentucky's secretary of state, nearly $24 million to $11 million, and outside groups had spent another $14 million, split roughly evenly between the two, according to the Center for Responsive Politics.

A list of corporate donors to McConnell and his allied committees reads like the Fortune 500, from Citigroup to Raytheon. Kentuckians for Strong Leadership, a group set up by McConnell allies, touts large contributions from real estate tycoon Donald Trump, venture capitalist Lawrence DeGeorge of Florida and oil executive Curtis Mewbourne of Texas.

Many of his ads, and much of his campaign stump speech, focus on linking Grimes to Obama. When Grimes aired an ad recently saying "I'm not Barack Obama," McConnell hit back with an ad linking her to Obama's agenda on gun control, foreign policy, Obamacare and coal regulations, even though she opposes the president on the latter.

SENSE OF HUMOR

McConnell's campaign strategists also have tried to turn his public image to his advantage and show he has a sense of humor about it.

When Obama joked last year about the criticism he receives for not reaching out to Republican leaders - "Really? Why don't YOU have a drink with Mitch McConnell?" - the senator responded on Twitter with a smiling picture of himself sitting at a bar with a beer, facing an empty chair and a glass of red wine.

But Kentucky voters still have a hard time loving McConnell. Asked to pick a word or phrase to describe him, the most frequent choice was "experienced" at 39 percent, but "arrogant" and "Washington insider" were next at 33 percent each.

For Rodney Nace, 37, a maintenance technician at a uranium byproducts plant in Kevil, Kentucky, McConnell's experience counts for more than his personality.

"As long as he's got the experience and knows what's going on, it doesn't matter if he's boring or hyper or whatever," Nace said after hearing McConnell for the first time at a campaign event. (Additional reporting by Gabriel Debenedetti; Editing by John Whitesides and Ross Colvin)