She first ran after two-term DFL incumbent Jason Isaacson announced he would seek election to the Minnesota State Senate.
From 2019 to 2020, she served as an assistant majority leader for the DFL House Caucus and vice chair of the Environment and Natural Resources Policy Committee.
[20][21] Becker-Finn offered an unsuccessful amendment to a 2017 public safety omnibus bill that would have increased penalties for protesters who block freeways, arguing it is a limit on free speech.
[22] She called the city of Minneapolis's backlog of untested rape kits "unacceptable" and pledged to work to get them tested, and authored legislation that would expand the definition of "mandatory reporters" in cases of sexual harassment and assault.
[29][30] Two legislators, Dan Schoen and Tony Cornish, resigned amid multiple complaints from lobbyists, staff and fellow lawmakers.
[37] She has sponsored legislation to increase outdoor education opportunities for Minnesota children and disadvantaged communities, including passing the bipartisan "No Child Left Inside" program.
[42][43] In 2019, Becker-Finn authored legislation that banned nonessential use of firefighting foam that contains PFAS chemicals due to their health and environmental risks.
[46] She has been a longtime supporter of tougher restriction on Minnesota's deer farms, and has criticized the Board of Animal Health's oversight of the industry.
[47][48] She passed a bill requiring owners to euthanize their herd when CWD is found, double-gate their properties, and undergo mandatory inspections to prevent further spread.
The provision passed the House but not the Senate, and the lake was renamed by the Department of Natural Resources after a court appeals process.
[59][60] Becker-Finn has spoken out publicly against offensive Native American depictions such as those in Halloween costumes and professional sports teams mascots.