Langone, the co-founder of The Home Depot, was one of the leading -- and most vocal -- voices pushing Christie to run for president in 2012 and continued to support him in his 2016 run, which ended Wednesday.
Weaver said Langone reached out to Kasich's campaign and offered to help on both the finance side and on making connections to the business community.
"You can use any advantage you can get in the both the business and finance world so we're really happy to have him," Weaver said on a conference call with reporters.
Kasich invested heavily in New Hampshire, a move that paid off when he placed second in Tuesday's primary. The finish has already paid dividends on the fundraising side, Weaver said, though he declined to elaborate on how much has been raised over the last two days.
For Kasich, the emergence of new backers will become especially important in the days ahead. Right to Rise, the super PAC backing Jeb Bush, will start airing an ad attacking Kasich on Friday. The goal will be to dampen any momentum he has coming out of New Hampshire, according to a person familiar with the spot. Bush's campaign has also already made clear it will be targeting Kasich in the days ahead.
Kasich finished 2015 with $2.5 million in the bank. New Day for America, the super PAC supporting Kasich that dropped significant resources into backing his New Hampshire effort, finished 2015 with $2 million cash on hand, according to filings with the Federal Election Commission.
The Ohio governor trails competitors Bush, and Florida Sen. Marco Rubio, in organization and resources in the state, Weaver said the campaign did expect to win delegates by the time the state's primary is complete. Kasich is in South Carolina now, but will head to Michigan for a bus tour at the start of next week and then a stop in Virginia, before heading back to the state -- moves that underscore the campaign's push to strike strong finishes in March primary states.
Before Christie dropped out, Langone had donated $250,000 to America Leads, the super PAC supporting Christie, according to FEC filings. He also donated the maximum $2,700 to Christie's campaign.