In its inaugural tweet, @TheIranDeal linked to a resource page about the agreement between Iran and world powers to curb its nuclear programme.
"The historic #IranDeal succeeds in verifying that Iran cannot obtain a nuclear weapon," the first tweet said.
White House spokesman Josh Earnest said the Twitter account would be used as an advocacy tool, and also a means to inform the public about the agreement.
"We are rolling out some new online tools that we'll use to advocate for the recently announced agreement to prevent Iran from getting a nuclear weapon," Earnest told reporters.
The account features a photo of the deal's leading negotiators, including US Secretary of State John Kerry and his Iranian counterpart Mohammad Javad Zarif.
The unveiling of the account comes as Congress was yesterday given 60 days to debate the deal, which is likely to be a bitter battle.
Congress cannot amend the terms of the deal, but can vote to approve or disapprove the accord.
Many Republican lawmakers say the agreement rewards Iran's bad behavior.
The White House said the new resource page is a "repository of information about the deal including infographics, video and fact sheets to help members of Congress, the American public and even all of you as you cover this story."
Within hours of setting up the Twitter account, at least one spoof Twitter handle appeared online, @TheIranBomb, with a similar profile photo, linking to a story about Saudi Arabia's reported plans to build its own nuclear programme.