"I think we all believe that Kevin is the right person. ... Our leadership team, I'm saying," the Wisconsin Republican told NBC News in an exclusive interview released Friday.
Ryan told NBC that he believes House Majority Whip Steve Scalise — a reported candidate for the role along with McCarthy — thinks the majority leader is the best person for the job. Ryan's decision not to run for re-election later this year set up a potential race between the two key Republicans to succeed him.
Scalise has said he will not mount a bid to lead House Republicans if McCarthy does. A member of the hardline conservative House Freedom Caucus, potentially Rep. Jim Jordan of Ohio, may try to become the GOP leader, complicating matters for McCarthy.
Ryan told NBC that he felt comfortable leaving the House partly because of the quality of the leadership team behind him.
McCarthy, 53, has represented California in Congress since 2007. He pulled out of a previous bid for House speaker in 2015 after he publicly suggested that a congressional panel investigating the deadly 2012 attack on U.S. facilities in Libya aimed to hurt Democrat Hillary Clinton's presidential chances.
Ryan eventually became speaker, a job he says he took reluctantly.
Ryan's announcement came ahead of a tough fight for Republicans to hold on to their House majority in November's midterm elections. The House speaker believes his retirement will not affect the GOP's ability to control the chamber, as he will continue to raise money and campaign for candidates.
Ryan told NBC he believes he will hand over the House speaker post to his successor, not the House minority leader job in a Democratic-majority chamber.
Helping to raise money for other candidates is a key part of a House leader's job. Through the first three months of the year, McCarthy had a significant fundraising edge over Scalise.