After leaving office, he was appointed CEO and executive director of the National Fish and Wildlife Foundation, a non-profit conservation organization created by Congress in 1984.

From 1987 to 1990 and from 1990 to 1995, he was affiliated with the offices of Congresswoman Virginia Smith (R-NE) and Congressman Pat Roberts (R-KS) and with the Committees on Appropriations and House Administration, respectively.

[2] On November 18, 2005, Trandahl resigned as Clerk to accept a position as the executive director of the National Fish and Wildlife Foundation.

[2] Later, he testified before the House Ethics Committee that he had warned the Speaker's office several times of his concerns about Congressman Foley's behavior toward them.

[6] In 2015, Trandahl signed an amicus brief to the Supreme Court of the United States in favor of nationally legalizing same-sex marriage.