Speaker John A. Boehner’s top policy adviser is leaving Boehnerland to head lobbying efforts at American Express.

Brett Loper, the deputy chief of staff for Boehner, is departing the speaker’s office after leading Boehner’s policy shop for two and a half years.

“Brett has been an invaluable asset, not just to my office, but also the entire House Republican team,” Boehner said in a statement Monday. “From our work to cut spending and reform our entitlement programs and broken tax code, to our efforts to enact free trade agreements and increase the supply of American energy, Brett has been at the center of every debate, and I have always benefited from his strategic advice and counsel.

Loper, a member of Roll Call’s Fabulous 50 list of influential staffers, came to Boehner’s office after a stint as the senior executive vice president of the Advanced Medical Technology Association. Before that, he was the Republican staff director on the House Ways and Means Committee from January 2007 to April 2008, and the chief of staff for then-Rep. Jim McCrery, R-La., from February 2006 to January 2007.

On Monday, Loper called American Express “one of the most admired companies in the world” and said he was “both humbled and honored” to work for AmEx.

A senior GOP leadership aide said Loper wanted more time and flexibility for his three young children and his wife. The aide said Boehner asked Loper to stay on through the early part of the 113th Congress, and he did.

Loper fills a vacancy left by Arne Christenson, who left the senior vice president job at American Express in March to head the policy and politics team at the American Israel Public Affairs Committee. The interim head of lobbying for AIPAC, Bobby Thomson, left recently for Visa.