Many people were surprised when Kentucky Republican Rep. Thomas Massie decided to throw his support behind House Speaker Kevin McCarthy last week.

In the past, Massie has often been at odds with leaders of his party in Congress, so there was some surprise on Capitol Hill when Massie didn't join the 20 Republicans who voted against Kevin McCarthy for Speaker last week.

“I’m almost surprised I didn’t join them," Massie told Spectrum News. "You have your 'never Kevins' I was kind of a 'barely Kevin.'"

Instead, he backed McCarthy in all 15 rounds of balloting.

That's a major change from almost eight years ago, when Massie was a ‘never Kevin,' part of a group that worked to keep McCarthy from the top job when John Boehner stepped down as speaker. McCarthy ultimately withdrew from that speaker's race, and Paul Ryan took on the role instead.

“Under Paul Ryan, what we saw was more power vested into the speaker, so what I learned in that fight was you can change the person and you haven’t changed this place,” adding: “Unless you get new rules and new ways of doing things, the place won’t change."

This time around, Mccarthy ultimately prevailed, finally being elected House speaker early Saturday morning after almost a week of voting. The California Republican has been criticized by some moderates for making too many concessions to conservatives to win their support. But Massie says those concessions are exactly why he supported McCarthy. 

“Kevin has given us so many changes to this institution that will outlast him," Massie said. "Whether he lasts six years, two years, or six days into his speakership, these changes are fundamental." 

Massie says he helped facilitate negotiations between McCarthy's camp and the 20 Republican lawmakers who opposed the California Republican. 

“One of the things I’m most excited about is the ability for any member – whether you’ve been here a day and just been sworn, in or been here 20 years – [to be able to] walk on the floor when they are debating a spending bill and offer an amendment to cut spending on anything inside of that bill,nd we have to take a vote on it,” Massie said. 

That rule change gives individual members more leverage to delay legislation, a power that Massie can very well use. 

Massie has earned himself the nickname "Mr. No" for his opposition to a substantial amount of legislation, including bills that have widespread bipartisan support. For instance, last month, Massie voted against the National Defense Authorization Act, the annual military spending bill which passed the House in a 350-80 vote.

Massie has previously expressed that Republicans' slim majority in the House – 222 to Democrats' 212 – was not necessarily a bad thing. When asked by Spectrum News on Friday if he still believes that, Massie replied that he likes "what has played out over the last three days."

"The Democrats had the exact same thing going on when they took the majority – but they did it behind closed doors," Massie said.

“This is all playing out in public here for Republicans, I’m glad we are litigating this now,” he added. 

Massie’s new influence will be playing out in public as well: McCarthy will need the support of almost every Republican member to get the party’s priorities through the House.

In short, the new speaker will need the lawmaker known as "Mr. No" to vote "yes" time and time again.

CORRECTION: An earlier version of this story had a quote from Rep. Massie which contained an error. This article has been updated to accurately reflect Rep. Massie's quote to Spectrum News.