The senator appeared on ABC News and spoke with journalist Jon Karl, who asked the lawmaker about her stance.
"For any member of Congress to suggest its OK to leak classified information because you agree with the cause is terribly irresponsible," Mr Graham replied.
Ms Greene issued a tweet on 13 April defending Jack Teixeira — who she mistakenly called Jake — a US Air National Guardsman who allegedly leaked sensitive documents to members of his private Discord server. Mr Teixeira was not acting in a whistleblower capacity when he leaked the documents, but allegedly hoped to use the documents to impress his teenage friends in the server.
"Jake [Jack] Teixeira is a male, christian, and antiwar," she wrote. "That makes him an enemy to the Biden regime."
She went on to claim that he "told the truth about troops being on the ground in Ukraine and a lot more."
"Ask yourself who is the real enemy," she wrote. "A young low level national guardsmen? Or the administration that is waging war in Ukraine, a non-NATO nation, against nuclear Russia without war powers?"
Mr Graham said what Ms Greene and other boosters — like Fox News' Tucker Carlson — "are suggesting will destroy America's ability to defend itself."
"That it's OK to release classified information based on your political views," he said. "That the ends justify the means. It is not ok. If you're a member of the military intelligence community, and you disagree with American policy, and you think you're going to be ok when it comes to leaking classified information, you're going to go to jail."
The Senator said it was "one of the most irresponsible statements you could make."
"There is no justification for this," he said.
Ms Greene posted a fake image of Mr Graham to her Twitter account in which the senator appears to be holding a can of Bud Light featuring trans influencer Dylan Mulvaney. The original photo shows Mr Graham holding a glass of beer.
There was no text to accompany the photo so the image may not be a direct rebuttal to Mr Graham’s rebuke.
The congresswoman also told right-wing commenter Charlie Kirk that she believes there needs to be an “opposition party” if Republicans won’t address the “serious problems” the nation is facing.
Ms Greene has been a frequent critic of the US’s involvement with Ukraine’s defense against Russia’s invasion.
Mr Teixeira was arrested earlier this week by federal law enforcement. He was formally charged on Friday for leaking classified documents.
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