He was appointed by President George W. Bush to serve as Minnesota's U.S. Attorney, a position he held from 2001 to 2006. He also held this position under President George H.W. Bush during the years 1991 to 1993. Heffelfinger has a long record of work on issues of importance to the Native American community, and serves on the Board of Directors of the Family Advocacy Center of Northern Minnesota in Bemidji.