Chellie was elected to the Maine State Senate in 1992, representing Knox County. In 1996, Chellie was chosen by her peers to be the Maine Senate Majority Leader. She helped lead the Senate for four more years, until leaving office due to term limits. As a Senator, she fought for economic and social justice, taking on powerful adversaries - most notably the pharmaceutical lobby. In her last session, Pingree sponsored one of the nation's first prescription drug pricing bills, MaineRX. After a legal fight that led all the way to the U.S. Supreme Court, the bill became law, and has since been a model for states around the country working to lower prescription drug prices.
From 2003 to 2007, Chellie served as the National President and CEO of Common Cause, a non-partisan citizen activist group with nearly 300,000 members and 35 state chapters. Common Cause's mission is to help citizens make their voices heard in the political process and to hold their elected leaders accountable to the public interest. Under Chellie's leadership, Common Cause increased its membership and diversified its agenda to include limiting media concentration and consolidation, promoting Net Neutrality, and election reform, while continuing to pursue its traditional goals of campaign finance reform and oversight of government ethics and accountability.
In 2008, Chellie was elected to Congress from Maine’s 1st Congressional District—the first woman elected to Congress from that District. She has previously served on the House Rules Committee and Armed Services Committee. She currently sits on the powerful House Appropriations Committee, chairing the Subcommittee on Interior and the Environment, the Subcommittee on Agriculture, and Subcommittee on Military Construction and Veterans Affairs. She also sits on the House Agriculture Committee.
Among other issues important to Mainers, Chellie has been an advocate in Congress for reforming federal policy to better support the diverse range of American agriculture—including sustainable, organic, and locally focused farming—as well as to reduce food waste. Many provisions from comprehensive legislation she introduced to make these reforms were passed in both the 2014 and 2018 Farm Bills. She received a 2017 James Beard Leadership Award for her national leadership in food system reform.
Chellie has also been recognized for her leadership on a number of other issues, including assisting survivors of military sexual trauma, strengthening the creative and arts economy, and helping coastal communities address threats to their future.