Kevin Poe, of Manchester, Conn., made his initial appearance Tuesday in federal court in Hartford, Conn., and was released on $10,000 bond. An email message left for deputy federal public defender Deirdre Murray was not immediately returned.
Poe was indicted in Los Angeles on two counts: conspiracy and unauthorized impairment of a protected computer. If convicted of both, he faces up to 15 years in prison.
Poe and others linked to Anonymous conducted a "denial of service" attack over a five-day period last October against Simmons' computer systems, sending tens of thousands of electronic requests designed to overload the server and render www.GeneSimmons.com useless.
Poe used a computer program favored by Anonymous that sends extremely large requests over a network in an attempt to overwhelm a target computer, according to the indictment.
Authorities didn't say why Simmons was targeted, but he made comments against copyright infringement at a convention in Cannes, France, days before the cyber attack.
No other arrests have been made.
Representatives for Simmons couldn't immediately comment about Poe's arrest because they weren't aware of it.