Christine Milne was elected to the Tasmanian parliament in 1989 and became Tasmania's first female political leader in 1993. She lost her seat of Lyons in 1998 after Tasmania reduced its number of MPs.

Before entering politics, Senator Milne had earned a reputation for activism on environment and heritage issues, including the campaign against the Franklin Dam and later the Wesley Vale pulp mill.

Elected to the Australian Senate

Elected at the 2004 election, Senator Milne entered the Australian Senate in 2005 and immediately took on the climate change and energy portfolios, which she has retained to this day.

In 2008, she was elected deputy leader of the Greens under Bob Brown and was returned at the 2010 election with a record Greens vote.

National Greens leader

In 2012, after Bob Brown announced his resignation from Parliament, the party elected senator Milne as leader.

Taking on the "daunting task", Senator Milne said she would continue to work for Mr Brown's "values of looking after our country and our people, now and into the future". 

Deal with Labor

Senator Milne was deputy leader when Bob Brown and then prime minister Julia Gillard inked a deal to support Labor's minority government in September 2010.

The Greens secured a long list of demands in the deal, which opposition leader Tony Abbott attacked for being dirty and secretive.

Carbon tax passed

In November 2011, the Labor government passed the carbon tax bills with the crucial support of the Greens. Still holding the climate change portfolio, Senator Milne had been part of negotiations that resulted in Australia's high-emitting companies paying a $23 per tonne carbon price.

Senator Milne had been integral in the voting down of Labor's original emissions trading scheme. The loss of this vote had major implications for the Rudd Labor government and climate change politics generally.

Resignation

On Wednesday March 6, 2015, Christine Milne announced her resignation from the leadership and from federal parliament.

"It is with a mix of optimism, pride, excitement and sadness that I am resigning," Senator Milne told assembled media at Parliament House.

Senator Milne's departure has made way for generational change in the Greens leadership. Senator Richard Di Natale, the party's first Victorian Senator, was elected their first leader from mainland Australia.