Born in Bradford, Pennsylvania, Walker graduated from Penn Manor High School.

Walker won the Republican nomination to succeed Eshleman from the 16th District, including all or part of Lebanon, Lancaster, and Chester counties.

[1] Michael Barone and Grant Ujifusa wrote that Walker was "scrappy, good humored, and ready to push his principles forward even at the cost of being mocked."

Walker also led a campaign against the rewriting of the Congressional Record and had the practice banned in the 104th Congress when Republicans won control of the House.

Congressional Quarterly wrote that "he has raised too many hackles and rubbed too many nerves to be very popular" in the House, but the voters back in Pennsylvania only once gave him less than sixty-five percent of the vote.

In 2001 he was appointed by President George W. Bush to chair the Commission on the Future of the United States Aerospace Industry.

In October 2016 he was appointed space policy adviser of Donald Trump's presidential campaign.