Simpson served in the Wyoming House of Representatives (1965–1977) and won election to the United States Senate (1978).

He has been a vocal proponent of amending the U.S. Constitution to overturn Citizens United v. FEC (2010) and allow Congress to set reasonable limits on campaign spending in U.S.

[4] Mineta and Simpson served together in Congress, and on the Board of Regents of the Smithsonian Institution, and remained close friends.

Pete Simpson was the 1986 Republican gubernatorial nominee, having sought the office while his younger brother was serving in the U.S.

In that brief, in support of the claimant in the Supreme Court case, Simpson admitted that, as a juvenile, he had been on federal probation for shooting mailboxes and punching a cop and that he "was a monster".

He played a game with his friends in which they shot at rocks close to one another, at times using bullets they stole from the local hardware store.

Simpson teaches periodically at his alma mater, the University of Wyoming at Laramie, with his brother Pete.

[22] In that capacity, Simpson recruited former President Gerald Ford to serve on the RUC advisory board.

In 2002, Simpson was involved in the Wyoming Republican gubernatorial primary on behalf of former Democrat Eli Bebout of Riverton.

[25] Simpson was appointed in 2010 to co-chair President Obama's National Commission on Fiscal Responsibility and Reform with Erskine Bowles.

[26] Simpson has spoken extensively about the burden being placed on future generations by the structure of current entitlement programs.

In an opinion piece, "Young Americans get the shaft" published in The Washington Post on June 13, 2012, Matt Miller recounted asking Simpson (then a US senator) in 1995 how to fix this problem.

Miller stated that Simpson told him "nothing would change until someone like me could walk into his office and say, 'I'm from the American Association of Young People.

In an interview with Wyoming Public Radio, Simpson said: "I think most Americans would like to see reasonable limits on campaign spending.

[32] He supports LGBT rights, and equality regardless of race and society, color, creed, gender, or sexual orientation.

[38] The June 7, 1994, edition of the now-defunct supermarket tabloid Weekly World News reported that 12 U.S. senators were aliens from other planets, including Simpson.

The Associated Press ran a follow-up piece which confirmed the tongue-in-cheek participation of Senate offices in the story.

[40] In December 2012, Simpson filmed a "Gangnam Style" video for a campaign, with a man in a tin can costume.

In the video, Simpson admonishes younger Americans to make better use of their social media than "instagramming your breakfast and tweeting your first world problems."

He advises younger people to use their social media skills and resources to rally their friends to join The Can Kicks Back.

[42] In 2011, Simpson and Erskine Bowles were presented the Paul H. Douglas Award for Ethics in Government for their work on the National Commission on Fiscal Responsibility and Reform.