Story highlights Former New Hampshire GOP chairman Fergus Cullen announced his support for John Kasich on Thursday

Cullen cited Kasich's positive tone as one of the main reasons for the endorsement

Newport, New Hampshire (CNN) Ohio Gov. John Kasich snagged the highly coveted endorsement of former New Hampshire GOP chairman Fergus Cullen, his campaign announced Thursday, just weeks before voters head to the polls for the first-in-the-nation primary.

Cullen, who was deciding between Kasich, former Florida Gov. Jeb Bush and Sen. Marco Rubio of Florida, has attended more than 20 events held by candidates and hosted four candidates or potential candidates at his home for house parties.

He hosted one of Bush's first-ever events in New Hampshire back in March, before Bush became a candidate. He also hosted Kasich, Sen. Lindsey Graham of South Carolina (who dropped out in December and now supports Bush), and former Ambassador John Bolton, who decided not to run for president.

Cullen told CNN that he thinks Kasich has the best chance of winning New Hampshire and appreciates Kasich's positive and "consistent tone during this whole campaign."

"I've seen some other candidates have felt like they needed to dial up the anger on the stump in some kind of appeal to voters," he said.

Read More