Among her accomplishments, Genachowski credited her with brokering an agreement with mobile providers to end bill shock and said she spearheaded the effort to move broadcasters' public files to the Internet.
“Sherrese’s expertise in media, cable and broadcast issues is unmatched in the industry, and her list of accomplishments over the past four years is remarkable," Genachowski said.
"She was one of my most trusted advisers — a close confidant whom I consulted on almost every major decision and issue. She had the rare combination of policy expertise and people skills that you need to get big things done," the chairman added.
Smith's departure prompts questions about when Genachowski plans to step down from his chairman role. Speculation about when he plans to exit has been swirling for months.
Smith said her decision to leave the commission was not connected with the rumors about Genachowski's plans. She declined to comment on when the FCC chairman planned to step down.
"After four years there's not much else I could personally could do [at the commission], so I'm ready to move on to my next challenge," she said.
Smith had previously served as senior counsel to the chairman and a legal adviser on media, consumer and enforcement issues. Prior to joining the FCC, Smith was the vice president and general counsel of Washington Post Digital. She was also a member of the intellectual property team at law firm Arnold and Porter.
— This post was updated at 11:11 a.m. with comments from Smith