Senator Scott Ludlam built a reputation over more than nine years in Parliament as an outspoken, tireless, and aggressive fighter for online privacy rights, national security and environmental causes.
Mr Ludlam, 47, began his career as a staffer for party elder Robin Chapple in state politics and Senator Rachel Siewart before winning his own Senate seat in 2007.
Working his way up to co-deputy of the federal Greens, Mr Ludlam established an identity as a relentless campaigner against online censorship, first opposing the Federal Government's net filter and then the metadata retention scheme.
His portfolios include communications, international aid, defence, foreign affairs, nuclear technology and sustainable cities.
He took a brief break in the latter half of last year to deal with mental health issues including depression and anxiety.
He spoke quite openly about his mental health battle, posting on Facebook at the time that he had been dealing with the issue for some while.
Mr Ludlam managed to hold onto his Senate seat despite a 5 per cent swing against his party in the 2016 federal election.
In 2013, he briefly lost his seat after becoming embroiled in a complex electoral fight, but reclaimed it when WA was forced to go back to the polls when ballot papers were lost, compromising the result.
In March 2014, just before West Australians went back to the polls for the Senate re-run election, he gave a cutting speech to a near-empty Senate chamber, welcoming then prime minister Tony Abbott to WA, which went viral on social media and helped the Greens raise much-needed donations to help their election campaign.
He was the fifth Greens senator elected for Western Australia, and has his office in the traditionally left-wing, environmentally-conscious heartland of Fremantle.
In his maiden speech to Parliament in 2008, he described Australia and the world as "poised on the edge of a historic transformation", and cited science fiction writer William Gibson, saying: "The future is here. It's just not widely distributed yet."
His departure leaves just one Green for WA in the Senate, Ms Siewart.
Prior to entering politics, Mr Ludlam worked as a graphic designer.
He was born in New Zealand, but moved with his family to Perth at the age of eight.
