GSA Administrator Denise Turner Roth praised Chrousos in a blog post announcing her coming departure.
"A startup entrepreneur with a history of building companies in industries that are being disrupted, Phaedra brought that experience with her to government," Roth wrote. "The creation of the Technology Transformation Service would have not been possible without her vision and leadership. She helped scale 18F from a 'minimum viable product' to an organization that agencies recognize as a critical partner in delivering services to the American public. [She] helped improve everything from tenant satisfaction in our public building portfolio to the contracting process for small businesses."
GSA CIO David Shive will serve as acting commissioner, working with 18F Executive Director Aaron Snow until a permanent replacement is found. The GSA will search the public and private sectors, Roth wrote, in hopes of finding "excellent" candidates who can advance the mission of improving the public's experience with government.
Chrousos' last day with the GSA will be July 15, according to an official announcement.