Republican Adam Hasner, a former leader in the Florida Legislature, announced Monday evening he is running for the nomination to challenge Democratic Sen. Bill Nelson.

“I have been traveling to every corner of the great state of Florida,” Hasner, 41, said on “The Mark Levin Show,” a syndicated radio program. “I’ve met some great people and we’ve had an honest discussion about the failures of Washington.”

“That’s why tonight I wanted to come back on your show,” Hasner said, “to let you know that I’ve made my decision official, and am announcing my candidacy for the United States Senate to challenge Bill Nelson in 2012.”

Levin promptly endorsed Hasner, who accepted the influential host’s backing and plugged his resume and his conservative bona fides. He detailed his service as Florida House Majority Leader from 2007 through 2010, boasting that he was “originally selected to serve as the Majority Leader” by Republican Sen. Marco Rubio, Florida’s popular freshman Senator who served as state Speaker.

Early in the interview, Hasner sought to distance himself from former Florida Gov. Charlie Crist. Crist left the Republican Party and became an Independent in his attempt to win the 2010 U.S. Senate race in Florida against Rubio.

“As Majority Leader … we were fighting against Charlie Crist and those in the Charlie Crist camp in the Republican Party who wanted to move the party to the center and those who were saying the best way to beat the Democrats was to join them,” Hasner insisted, taking a not-so-subtle swipe at one of his competitors in the GOP Senate primary, former Sen. George LeMieux.

Crist appointed LeMieux in September 2009 to fill the remainder of retiring Republican Sen. Mel Martinez’s term. On his Facebook page, Hasner prominently displays a Web ad that includes a video of LeMieux saying, “I’d describe myself as a Charlie Crist Republican.”

“I was the one standing firm, saying ‘Republicans don’t need to be less partisan, we need to be more principled.’ And I think that’s the same type of fight we need right now,” Hasner told Levin.

The other major candidate Hasner will face in the primary is state Senate President Mike Haridopolos.

Hasner filed the official paperwork for his Senate campaign earlier this month, according to the St. Petersburg Times.

Last week, Hasner picked up the endorsement of authoritative conservative blogger Erick Erickson of Red State.