Lee is a Senator for NSW, and has been a passionate activist for environment and social justice movements over five decades. Her portfolios include housing, democracy, industry, animal welfare and gun control.

Lee is an Australian Greens Senator for NSW. Prior to this, she was a Greens MP in NSW Parliament for over a decade. Lee spent this time pursuing reform in key areas like the environment, mining, public education, industrial relations and public transport. One of her most influential campaigns has been to stop the corrupting influence of political donations.

Lee is well-known for her energetic work in environment and social justice movements over five decades. She co-founded AID/WATCH and was its director for five years. Lee has been a long-time advocate for asylum seekers and refugees and regularly visits Villawood Detention Centre.

Lee was an organiser of the 1983 Women for Survival Pine Gap peace camp, Secretary of the Union of Australian Women (NSW Branch) and an organiser for Women Against Global Violence. In the early 1980s Lee was a member of the NSW Women’s Advisory Council that advised the NSW Premier.

In 2001 Lee initiated the annual Juanita Nielsen Memorial Lecture to honour the achievements of the community activist who was murdered in the 1970s for her stand against over-development in Kings Cross.

Lee has worked with the Rainforest Information Centre and for a number of trade unions.  She trained as a zoologist and botanist.