In February 2018, Metzger announced that she would challenge longtime Republican Senator John Bonacic for his seat. Several months later, Bonacic announced that he would retire. In September, Metzger defeated Pramilla Malick in the Democratic primary, and faced Orange County Clerk Annie Rabbitt in the general election. A closely watched race, the seat was seen as one of the most competitive of the cycle. In an overwhelmingly Democratic year, Metzger defeated Rabbitt 52% to 48%.

With Democrats winning the majority in 2018, Metzger is now serving as Chair of the Senate Agriculture Committee.

In 2001, Metzger and her husband moved to Rosendale, New York, a hamlet in the Hudson Valley. She later chaired the Rosendale Environmental Commission and served as Deputy Town Supervisor. In 2013, Metzger was elected to the Rosendale Town Council, and was re-elected in 2017..

In 1988, Metzger began work as a Public Affairs Coordinator with the United Nations, and later served as an instructor at the Walt Whitman Center for Culture and Politics of Democracy and Rutgers University.

Metzger was born and raised in New York City. She graduated from Oberlin College in 1987 and earned her Ph.D. in political science from Rutgers University in 2004. She is married with three children.

Jennifer “Jen” Metzger (born February 3, 1965) is a member of the New York State Senate, who has represented the 42nd district since 2019. Her district encompasses much of the Hudson Valley west of the river as well as portions of the Catskill Mountains. Metzger is a Democrat.