Jon Kyl, the former senator from Arizona. (J. Scott Applewhite/AP)

Former Sen. Jon Kyl (R-Ariz.), who retired from Congress in January as the second-highest ranking Republican in the Senate, has joined the lobbying group at Covington & Burling, the law firm plans to announce today.

Covington, the District’s largest law firm, has not historically been known for lobbying but in recent months has been pouring resources into improving its government affairs capabilities in Washington and Brussels. In October, the firm hired Dan Bryant, who led PepsiCo’s in-house lobbying shop, to grow the practice internationally.

Kyl, most recently the Senate Minority Whip, will be based in Covington’s Washington headquarters and advise companies on policy issues including cybersecurity, taxes, health care and national security.

“The firm’s clients are an incredible mix of really important business entities representing a wide spectrum,” Kyl said in an interview. “I’ve had enough experience in the Senate and House to know how to help them out.”

Kyl, a four-term congressman before being elected to the Senate in 1994, is an influential figure who has helped broker deals between Republicans in Congress and the Obama administration on key issues such as extending the Bush-era tax cuts to 2012. In late 2011, he was one of 12 members of the congressional “super committee” that sought and failed to reach an agreement on how to cut $1.5 trillion from the deficit.

Under ethics rules, senators cannot formally lobby Congress on someone else’s behalf for two years after leaving office. But Kyl said there is “a huge amount of work that can be done” in the meantime.

“[Clients] need advice and counsel from someone who knows how government works in Washington,” Kyl said. “That’s the kind of advice I can give without getting into lobbying. I can provide my insights into the people and process on Capitol Hill for them to take advantage of in the lobbying they do.”

As congressional gridlock and the elimination of earmarks have shifted much of the focus of lobbying from the House and Senate to the executive branch, law and lobby firms that once clamored to add members of Congress to their roster have shifted their sights to include leaders at influential agencies. Covington is no exception: Michael Chertoff, former secretary of Homeland Security, and John Dugan, former Comptroller of the Currency, have joined the firm since 2009.

“As government has grown and Congress has delegated more responsibilities to agencies ... that part of the practice has grown,” Kyl said. “But it certainly does not obviate the need for work on the legislative side as well.”