Senator Bob Brown gave up his medical practice in 1976 to help found the Tasmanian Wilderness Society to protect the state's natural resources, including the Franklin River wilderness. The last free-flowing river in Australia, the Franklin winds through pristine rainforest on the island state of Tasmania. Recognizing its diverse and unique flora and fauna, UNESCO added Tasmania's western wilderness, including the Franklin River, to the World Heritage List in 1982. That same year, however, the Tasmanian state government announced its plan to open up the region to mining, forestry and hydroelectric development, including a dam that would have flooded vast areas of rainforest, the world's last stands of ancient Huon Pine and ice-age archaeological sites.

Brown and the Tasmanian Wilderness Society immediately launched a nationwide campaign to halt the construction of the dam. For his role in a non-violent blockade of the dam site in 1982, Brown was arrested and imprisoned for 19 days. The day of his release he won a seat in the Tasmanian Parliament. The battle to save the Franklin continued, the case going to the High Court of Australia, which stopped construction on the dam in 1983. Brown was leader of the Green Party in the Tasmanian Parliament from 1989 to 1992, when the Greens held the balance of power. During that time, they were instrumental in extending the Tasmanian Wilderness World Heritage Area by 650,000 hectares. Brown used his Goldman Prize money to establish the Australian Bush Heritage Fund, to acquire and protect threatened areas of high conservation value. As a member of parliament, Brown continued to participate in peaceful demonstrations, including one in 1992 when pro-loggers fired gun shots and fire bombed environmentalists' cars. He was twice arrested and jailed for peaceful protests against the bulldozing of a gravel road through Tasmania's Tarkine Wilderness in 1995.

Brown is now a national spokesperson for Australia's Green Party, which he helped to establish in 1992, and in 1996 was elected to the Australian Senate in Canberra where he and a fellow Green hold the critical balance of power in the 76 seat chamber. The Australian Greens are currently working to protect the rights of indigenous Australians, and are fighting massively increased woodchipping in native forests and plans to mine uranium at Jabiluka, in the middle of Kakadu National Park, against the wishes of the traditional landholders.