WASHINGTON — In his first 100 days as the chairman of the Federal Communications Commission, Tom Wheeler persuaded mobile phone companies to agree on rules about unlocking consumers’ phones, cemented an effort to increase the reliability of calls to 911, proposed tests to do away with old-fashioned telephone networks and freed $2 billion to connect schools and libraries to the Internet.

Those were the easy tasks. In the coming days, the telecommunications, media and Internet industries will be watching to see how Mr. Wheeler responds to last month’s federal appeals court decision that invalidated the rules created by the F.C.C. in 2011 to maintain an open Internet.

Mr. Wheeler has said that he views the decision, which many people saw as a setback for the agency, as an opportunity. He contends he can use it to assert the commission’s broad legal authority to enforce equality and access throughout the networks on which Internet traffic travels — a concept known as net neutrality.

Stressing the depth of his conviction, Mr. Wheeler answered a reporter’s question at a recent news conference about how the F.C.C. would react by pounding the lectern, emphasizing each word: “We will preserve and protect the open Internet.”