The former chief of staff to Gov. Tom Wolf announced her Senate candidacy Tuesday in a video posted to YouTube.
Katie McGinty will enter a Democratic primary against former U.S. Congressman Joe Sestak, who lost to incumbent Republican Pat Toomey in the 2010 general election.
McGinty said in the video her platform will include supporting the middle class, advocating for affordable health care and job training, boosting the minimum wage, improving infrastructure, creating clean energy jobs, protecting Social Security and making college affordable.
"Above all, we need to focus on the needs of the middle class, on better jobs and higher wages and firm up that basic bargain that has been the secret to America's strength - anyone willing to work hard can make it and get ahead," McGinty said.
McGinty ran for governor last year, finishing fourth in the Democratic primary. She previously served as the Department of Environmental Protection secretary during the Rendell administration.
She resigned from her post in the Wolf administration last month.