Stanton, who made the announcement Friday on Twitter, will head the company's international strategy.
Stanton worked on new-media strategies for President Obama's 2008 campaign, served as White House director of citizen participation and in December began helping the State Department use social media in international diplomacy and aid. Secretary of State Hillary Clinton has focused on Internet freedom as an important plank of U.S. foreign policy.
Stanton also organized a group of engineers to create a free texting service to help Haiti in the aftermath of that country's devastating earthquake. She kept followers up to date on politics and technology through her Twitter account, kateatstate.
Stanton is a key hire for Twitter, which is taking a greater interest in Washington as the company's international profile rises.
The San Francisco Internet company, with 200 employees, is seeking to hire its first Washington-based employee to be its liaison with federal regulators and lawmakers.
In February, Twitter hired Sean Garrett as its vice president of corporate communications. Garrett co-founded the technology policy public relations shop 463 Communications, which counts lobbying group TechNet among its clients.
For years, Silicon Valley has been looking to bridge its digital divide with Washington. Major technology companies have big lobbying operations to get lawmakers up to speed on pressing issues as well as on new gadgets and technologies.
The explosive growth of social media is sending new but already major players such as Facebook Inc., which runs the world's largest social networking site, to the nation's capital.
Stanton was just one of the technology evangelists whom the Obama administration recruited, mostly from Silicon Valley, to propel Washington into the digital age.
Andrew McLaughlin, Google's former head of global public policy, works as the administration's deputy chief technology officer. Jared Cohen, author of "Children of Jihad," serves on Clinton's policy planning staff and as a link to Silicon Valley, leading delegations of prominent technology figures such as Twitter Chairman Jack Dorsey to Russia and Iraq.
Internet pioneers also are taking visible roles.
Tim O'Reilly, founder of O'Reilly Media, a company that publishes magazines and books and hosts events, held an exposition in Washington this spring to encourage the "Gov 2.0" movement.
And Craigslist founder Craig Newmark is spending time in Washington to encourage greater use of technology and greater transparency.