Eddie Lazarus, chief of staff of the Federal Communications Commission, on Tuesday announced his resignation, ending a tenure marked by brutal battles over Internet access rules and the reviews of two massive mergers.

FCC Chairman Julius Genachowski has not appointed Lazarus’ successor.

Lazarus said he would stay through the end of January and does not have immediate plans after his departure.

Lazarus, the former head of the Los Angeles office for the Akin, Gump law firm, came to the FCC in June 2009 with no telecommunications policy experience. He was quickly swept up in a contentious battle over so-called net neutrality rules that aimed to prevent Internet service providers from blocking Web sites on their networks. He orchestrated weeks-long negotiations between the nation’s biggest telephone and cable firms along with Google and Skype over those rules, which are being challenged in federal court.

“Eddie has worked tirelessly to refocus the FCC on broadband Internet and unleash its opportunities,” Genachowski said.

Lazarus has worked to defend the agency against legislative proposals by some Republican lawmakers to strip away some of its powers. The agency is also under scrutiny by some GOP lawmakers for granting key permission to mobile satellite service provider LightSquared, whose technology was found to interfere with global positioning systems used by consumers and the military.

The agency also was under the spotlight for industry-altering mergers that could affect how consumers access and pay for media and telecommunications. The FCC in January approved a $30 billion venture between Comcast and NBCUniversal, but last month opposed a $39 billion merger between AT&T and T-Mobile, saying it would harm consumers and competition.

High on the FCC’s agenda while Lazarus was chief of staff was an effort to bring high-speed Internet service to rural areas. The agency recently retooled a $4.5 billion landline telephone fund for the purpose.

After that was accomplished, Lazarus said he felt ready to leave.

“It’s been an exhilarating and transformative experience and I’m grateful for the opportunity,” he said.