Parliamentarian and member of the ruling Social Liberal (PSL) party Carlos Jordy tweeted out the thinly-veiled threat on Thursday in a string of messages.
"You can not confront our institutions and authorities, committing crimes against national security and not imagine that [you] can be criminally punished and DEPORTED," the lawmaker said, adding "your case is already being investigated."
Greenwald replied to the threat Friday afternoon with a Twitter thread of his own, denouncing Jordy's warning and suggesting he had no plans to leave the country anytime soon.
Democracies do not 'deport' journalists for doing journalism.
"I have been living in Brazil since 2005. I have been married for 14 years with a Brazilian and adopted 2 Brazilian children," Greenwald said. "I invested my life in the future of Brazil."