Genachowski said the commission is still accepting public comments and that it would be "unusual" to close the proceeding.
The Communications and Technology subcommittee recently held hearings on proposals that would allow a United Nations agency to gain more control over the Internet. Shimkus noted that there was a consensus among lawmakers of both parties, as well as members of the FCC, that greater international control over the Internet could stifle innovation and restrict freedom.
Shimkus said closing the Title II docket would provide certainty to businesses and Internet users.
Rep. Mary Bono Mack (R-Calif.), who sponsored a resolution unanimously approved by the committee opposed to U.N. Internet regulation, also argued that the FCC should not try to expand its power over the Internet.
But classifying the Internet under Title II would put the FCC's net-neutrality regulations on firmer legal ground. The commission's net-neutrality rules, which it adopted in 2010, bar Internet service providers from slowing down or blocking access to legitimate websites.
Supporters of the rules say they are necessary to protect the openness of the Internet from manipulation by Internet providers.
Verizon has sued the FCC in federal court, arguing that the rules go beyond the commission's authority to regulate "information services."
Genachowski disagreed with the Republicans that classifying the Internet under Title II would lead to government control of the Internet.
"I believe very strongly in Internet freedom ... no gatekeepers of the Internet, public or private," Genachowski said.
The two other Democratic FCC commissioners sided with Genachowski, saying that net neutrality protects consumer choice.
Rep. Mike Doyle (D-Pa.) also defended Genachowski. He said the criticism is "misinformed" and that net-neutrality creates an open Internet that allows consumers to choose what content they want to access.
But the two Republican commissioners said the FCC should close its Title II docket.
Commissioner Ajit Pai, appearing in his first hearing before the House panel, said leaving the docket open will only "further chill investment."
Commissioner Robert M. McDowell said he often speaks to foreign audiences about the importance of Internet freedom and that people ask him why the FCC is still considering expanding its own powers over the Internet. He said it is hypocritical of the agency to not close the Title II docket.
—Updated at 6:02 p.m.