Democrat Tammy Baldwin is the first woman elected to the U.S. Senate from Wisconsin and the first openly gay senator.
"But I didn't run to make history, I ran to make a difference," she told a crowd of supporters at her election headquarters in Madison Tuesday night.
Despite a bitter race in which she faced former Wisconsin Governor Tommy Thompson, she said her fight is just beginning.
"Here is the promise I want to make you, I will be a senator for all of Wisconsin."
Throughout her campaign, Baldwin told voters she would fight for the middle class. She echoed that commitment in her victory speech.
"I can't tell you how grateful I am for the trust that you've placed in me and all I can do is work as hard as I can to keep that trust," she said.
This senate seat has been held by a Democrat for more than five decades and Baldwin said she looks forward to representing the people of Wisconsin.
"We're all in this together," she told the crowd at Monona Terrace.