In 2011, Genachowski converted a $4.5-billion rural telephone fund into a subsidy to expand broadband Internet service. The agency is currently moving ahead with a plan to encourage TV stations to give up their rights to airwave frequencies for auction to cellphone service providers, which have struggled to keep pace with the booming demands for mobile data.
Genachowski said his agency took "strong steps to promote competition by blocking and modifying mergers when necessary."
The agency approved Comcast's purchase of NBC-Universal in early 2011, but imposed conditions on the deal aimed at protecting competition. The FCC, along with the Justice Department, killed AT&T's $39-billion bid to buy T-Mobile, saying it would have led to high prices and stifled competition.
In a controversial decision, Genachowski overrode Republican opposition to enact net neutrality regulations in late 2010. The rules require Internet service providers to treat traffic to all websites equally.
In a speech to commission employees on Friday, Genachowski touted that average broadband speeds have doubled under his watch and that the nation leads the world in the deployment of next-generation 4G LTE cellphone service.
"Because of [Genachowski's] leadership, we have expanded high-speed Internet access, fueled growth in the mobile sector, and continued to protect the open Internet as a platform for entrepreneurship and free speech," President Obama said in a statement.
Rep. Henry Waxman (D-Calif.), the ranking member of the House Energy and Commerce Committee, called Genachowski a "brilliant chair" who "transformed and energized" the agency.
But Genachowski's tenure was not without its critics.
Republicans and industry groups at times accused him of burdening businesses with unnecessary regulations and restricting Internet freedom.
Consumer advocacy groups, meanwhile, were disappointed that he didn't do more to crack down on powerful industry giants and that he failed to enact aggressive regulations to protect Internet users.
"He had the opportunity, but declined, to solidify the agency’s authority and ability to protect consumers with regard to broadband — the communications system of the present and future," Public Knowledge, a consumer group, said in a statement. "As a result, there is a real danger that the FCC will become a powerless and irrelevant agency as the nation’s communications networks change."
Free Press President Craig Aaron claimed that Genachowski "catered to corporate interests."
"His tenure has been marked by wavering and caving rather than the strong leadership so needed at this crucial agency," Aaron said.
Asked to respond to his critics, Genachowski said "robust debate is very healthy," but he insisted that he "revitalized the agency" with the goal of extending broadband, empowering consumers and protecting the Internet.
He cited the net neutrality rules as one of the top achievements of his tenure, arguing that they have led to an "increase in innovation and investment" in Internet services and infrastructure.
Verizon has sued to overturn those rules, claiming that the FCC overstepped its authority to regulate Internet services.
Many observers say the court is likely to scrap, or at least substantially alter, the net neutrality regulations. But Genachowski said he is confident the court will side with the FCC.
Updated at 5:05 p.m.