Mike Shields, the top aide at the Republican National Committee and a veteran political operative, is leaving the party committee to helm a super PAC dedicated to preserving and expanding the party’s House majority.

Shields has been appointed president of both the American Action Network, a 501(c)4 organization focused on issue advocacy, and its sister super PAC, the Congressional Leadership Fund. Shields, who begins work at the groups next Monday, is stepping down as chief of staff at the RNC, where he is being replaced by Katie Walsh, who had been the party committee’s finance director.

The move will put Shields at the center of policy debates on Capitol Hill, where Republicans now control both chambers, and of congressional campaigns in the 2016 presidential election year, when the GOP is expected to struggle to defend all of its House seats.

The American Action Network and the Congressional Leadership Fund have raised a combined $104 million since 2011 and have been among the largest outside spenders in House races.

Shields said he is looking forward to engaging both in policy debates as well as in the political arena.

“Now that Congress has been elected, there are going to be some fights on the floor that people on the center-right on our side of the ideological spectrum care about, and being able to mix it up in the policy fight and push some of those things is an exciting opportunity,” Shields said.

Shields replaces outgoing president Brian O. Walsh, who has led the American Action Network for four years and is joining Red Print Strategy, a consulting firm. Under Walsh’s leadership, the group has advocated for immigration reform and against President Obama’s healthcare overhaul.

Like the House Majority PAC on the Democratic side, the Congressional Leadership Fund is the primary super PAC for Republican House leadership and has been endorsed by Speaker John A. Boehner (R-Ohio). The group as well as American Action Network are chaired by former senator Norm Coleman of Minnesota.

In a statement, Coleman said he was “thrilled” to recruit Shields as president.

“Mike’s gifts and experience are exactly what’s needed to build on our growth and achievements,” Coleman said. “I’ll always be grateful for Brian’s remarkable leadership in growing these organizations and to have made an unmistakable impact on our nation’s policies and leaders.”

Fred Malek, a co-founder of the American Action Network and a prominent Republican donor from Virginia, said in a statement: “Our vision for center-right policy influence has become a reality with American Action Network’s success, and I’m proud to have the estimable Mike Shields lead us even farther.”

Shields has worked in Republican politics since 1994 and spent five years as former House speaker Newt Gingrich’s top political spokesman. He worked as chief of staff to Rep. David Reichert (R-Wash.) before joining the National Republican Congressional Committee as director of its independent expenditure program in 2010, helping propel the GOP to a historic 63-seat gain in the House. He remained at the NRCC through the 2012 cycle as political director.

At the RNC over the past two years, Shields worked with Chairman Reince Priebus in overseeing a transformation of the RNC spurred by its “Growth and Opportunity Project,” a post-mortem following Mitt Romney’s defeat in the 2012 presidential election.

Priebus and Shields narrowed the party committee’s focus to “core competencies,” making significant investments in data, technology and field operations while leaving television advertising and other campaign functions to super PACs and the campaigns themselves.

“In the current ecosystem we have, everyone has a unique role to play,” Shields said.

In a statement, Priebus credited Shields with being “a crucial part of our historic victories in 2014.”

“Our party underwent significant improvements while he was here, switching to a year-round political operation, with renewed focus on minority engagement, data and tech, and a more robust political infrastructure that has the RNC well positioned to win back the White House and hold our Republican majorities in 2016,” Priebus said.