After graduating from college, Loon became active in government at the national level. She was a legislative assistant to U.S. SenatorLarry Pressler from 1986 to 1988, and a lobbyist and legislative representative for Associated Builders and Contractors, a national trade association representing Merit Shop construction companies, from 1988 to 1990. She worked in several staff positions for the U.S. House of Representatives from 1990 to 1997, including legislative director, minority policy director, minority staff director, and staff director for the House Committee on Small Business (1995–1997), where she worked directly with the committee chair, Congresswoman Jan Meyers of Kansas. From 2003 to 2007, she was director of government affairs, lead federal lobbyist and legislative strategist for ACA International, a national trade association representing the credit and collection industry.[4][5][6]