NEW YORK, N.Y. – The chairman of the Federal Communications Commission, Julius Genachowski, on Friday announced his resignation in the “coming weeks.”

The country’s top telecommunications regulator told a staff meeting of his decision Friday morning. His impending departure was reported Thursday by several news outlets.

Genachowski, 50, was appointed in 2009 and has hewed a middle line between the desires of public-interest groups and the telecom industry, which hasn’t enamoured him to either side.

His tenure has seen continued adoption of broadband and ever higher Internet connection speeds, especially on the wireless side, but consumer groups saw the approval of Comcast’s acquisition of NBC as a mistake, while AT&T Inc. suffered a severe blow when its acquisition of T-Mobile USA was blocked.

“For those of us who represent the public, Chairman Genachowski’s term can best be described as one of missed opportunities,” said public-interest group Public Knowledge. Genachowski should have done more to assert the FCC’s authority over broadband, which is lightly regulated compared to the telephone, and to prevent consolidation in the industry, it said.

Rob Atkinson, president of the Information Technology and Innovation Foundation, a non-partisan think-tank , commended Genachowski’s FCC for its National Broadband Plan — the first comprehensive federal plan to stimulate the availability and adoption of high-speed Internet access — and for its efforts to put more radio spectrum to use wireless broadband.

“America’s broadband economy is thriving, with record-setting private investment, unparalleled innovation in networks, device and apps, and renewed U.S. leadership around the world,” Genachowski said Friday as he thanked the FCC’s staff.

Genachowski’s departure will follow that of Republican Robert McDowell, which leaves the five-member commission with a 2-1 Democratic majority until President Obama appoints a new chairman and commissioner.

Stifel Nicolaus analysts Christopher King and David Kaut said they believe the front-running candidate for next chairman is Tom Wheeler, a venture capitalist and former president of two major trade groups, for the cable and wireless industries.