ORLANDO, Fla. -- Central Florida's most controversial congressman now has an opponent with money to back him. Orlando businessman Bruce O'Donoghue announced Monday he's running against Democrat Representative Alan Grayson.

O'Donoghue already has some big endorsements behind him, former Senator Mel Martinez and ex-Lieutenant Governor Toni Jennings.

Congressman Grayson's people are already firing back, saying O'Donoghue has "fattened his wallet" on government contracts with his business. It’s a sign that this could be quite a fight.

O'Donoghue is the latest and, some think, the Republican's best chance to take down first term Congressman Alan Grayson.

“Hey, the American dream is at risk and we need somebody who understands Central Florida and represents the values from Central Florida to be in Congress,” O'Donoghue said Monday.

O'Donoghue officially kicked off his campaign for Congress in Winter Park. Joined by well-known Republicans Mel Martinez and Toni Jennings, O'Donoghue wants to convince voters he's a homegrown conservative, while casting Grayson as a liberal from New York.

“This is a very unusual year. I think people have had enough of the nonsense in Washington, needless partisanship,” Martinez said.

Controversial comments from Grayson have only added to his reputation and put a bulls-eye on his back for the national Republican Party. O’Donoghue will face State Rep. Kurt Kelly and Todd Long in the GOP primary, but political experts say it's too soon to count Grayson out.

“The Republicans keep saying Alan Grayson's the most endangered incumbent and they're going to beat him. They were saying that the night he won the election two years ago. And, on the other hand, they don't seem to be able to get a very high-profile, quality candidate,” UCF professor Aubrey Jewett said.

Monday, Grayson's spokesman said he wasn't available to talk about O'Donoghue entering the race, but rejected the claim that Grayson is a Florida outsider and pointed to his own experience in business before entering politics.