Reps. Howard Coble (R-N.C.), chairman of the Courts, Intellectual Property and the Internet Subcommittee, and Mel Watt (D-N.C.), the subcommittee's ranking member, also said they will back legislation.
Sens. Amy Klobuchar (D-Minn.) and Ron Wyden (D-Ore.) have introduced bills to legalize cellphone unlocking, and Rep. Anna Eshoo (D-Calif.) plans to push legislation in the House.
The White House endorsed cellphone unlocking on Monday in response to an online petition that gathered more than 114,000 signatures.
Since January, customers have had to obtain their carriers' permission to legally unlock their phones, even if they have completed their contract.
The Digital Millennium Copyright Act (DCMA) bans people from circumventing a "technological measure" to gain access to a copyrighted work. The law instructs the Librarian of Congress to grant exemptions to the ban. In 2006 and 2010, the Librarian of Congress exempted cellphone unlocking from the law's restrictions, but the wireless industry persuaded the agency last year to allow the exemption to expire.
CTIA, the wireless industry's lobbying group, argues that carriers already sell many unlocked phones and are often willing to unlock phones at their customers' request.
In a blog post on Friday, Joan Marsh, AT&T's vice president of federal regulatory affairs, said her company already unlocks phones and that the Librarian of Congress's decision will not negatively impact any AT&T customers.
"If we have the unlock code or can reasonably get it from the manufacturer, AT&T currently will unlock a device for any customer whose account has been active for at least sixty days; whose account is in good standing and has no unpaid balance; and who has fulfilled his or her service agreement commitment," she wrote.