The newly merged Prime Policy Group snagged one of Capitol Hill’s hottest lobbying prospects on Monday, hiring longtime Blue Dog staffer Vickie Walling, chief of staff to retiring Rep. John Tanner (D-Tenn.).

Following her boss’s recent retirement announcement, Walling was widely considered K Street’s No. 2 free agent after Tanner, an original member of the fiscally moderate caucus of House Democrats. Walling spent 20 of her 35 years as a staffer for Tanner, who was first elected in 1988.

“Vickie Walling is a legend on Capitol Hill and we are thrilled she has chosen to continue her career at Prime Policy Group,— firm President Scott Pastrick said in a statement. “Her decades of service and experience with the Blue Dog Coalition will solidify Prime Policy Group’s unique expertise in coalition building and full scale, strategic advocacy campaigns to achieve policy goals.—

Walling’s new employer formed in October from the remnants of two struggling lobbying shops, Timmons and Co. and BKSH & Associates Worldwide. BKSH executives Pastrick, a Democrat, and legendary GOP lobbyist Charlie Black assumed leadership of the new firm.

Meanwhile, Preston Padden, Disney’s chief lobbyist, is giving up his position as executive vice president of government relations and expects to retire in January 2011. Broadcasting & Cable first reported on Padden’s expected departure. Padden said he has accepted a position as senior fellow at the Silicon Flatirons Center at the University of Colorado Law School and as an adjunct professor there, according to an e-mail he sent to colleagues and friends.Padden did not immediately return a request for comment. It’s unclear who will take over for the longtime Republican entertainment lobbyist.

Richard Bates, former executive director of the Democratic Congressional Campaign Committee, is a likely contender.Padden has been at Disney since 1998. Previously, he was president of the ABC TV network and served as head of the former Association of Independent Television Stations and as CEO of News Corp.’s Sky Broadcasting.