Republican challenger Keith Rothfus has unseated U.S. Rep. Mark Critz in Pennsylvania's 12th Congressional District, which was redrawn during Republican-controlled redistricting to make it easier for the GOP win.
The defeat was the first for Critz, a Democrat, who replaced John Murtha, a veteran Democratic power broker, who died in office in February 2010.
Rothfus, a corporate attorney, supports free trade and repealing the health care reform package pushed by President Obama.
He also touted a plan similar to the one proposed by Wisconsin Congressman Paul Ryan, the Republican vice presidential candidate, which would keep Medicare unchanged for those 55 and older, while making the current form just one of several options available to younger people.
Rothfus' win was his first in a general election. He lost to former U.S. Rep. Jason Altmire in 2010. Altmire was defeated in the Democratic primary by Critz earlier this year.
In his victory speech, Rothfus thanked his family and supporters.
"I cannot thank you enough for the sacrifices you have put in financially, time wise, doors knocked and phone calls made. I will always be grateful," he said.
The Associated Press contributed to this story.