Fischer has been a leading figure in the German Greens since the 1970s, and according to opinion polls,[1] he was the most popular politician in Germany for most of the Schröder government's duration.

In September 2010, he supported the creation of the Spinelli Group, a Europarliamentarian initiative founded with a view to reinvigorate efforts to federalise the European Union.

During this period, he began attending university events, including lectures organized by left-wing revolutionary students by Theodor W. Adorno, Jürgen Habermas and Oskar Negt.

In the Deutscher Herbst (German autumn) of 1977, Germany was rattled by a series of left-wing terrorist attacks by the Red Army Faction (RAF) and Revolutionary Cells (RZ).

According to Fischer's own account, witnessing these events, particularly the kidnapping and murder of Hanns-Martin Schleyer and the Entebbe hijacking,[7][8] made him renounce violence as a means for political change.

In May 1981, the Hessian Secretary of Commerce Heinz-Herbert Karry was murdered with a firearm that in 1973 had been transported in Fischer's car, along with other weapons stolen from an American army base.

Some critics continue to charge that Fischer was the leading figure of a 1976 discussion that led to the use of Molotov cocktails in an upcoming demonstration in support of RAF member Ulrike Meinhof.

In 1985, Fischer became Minister for the Environment in the Landtag of Hesse in the first governmental Red-Green coalition between the Social Democratic Party of Germany (SPD) and the Greens.

[14] In September 2001, Fischer summoned Ahmad Azizi, the Iranian ambassador to Germany, for urgent talks after several reformist intellectuals – including Akbar Ganji, Mehrangiz Kar and Ezzatollah Sahabi – were given prison sentences of between four and 10 years for participating in a 2000 academic and cultural conference sponsored by the Heinrich Böll Foundation in Berlin in late 2000.

[15] In 2005, critics charged that Fischer's relaxing of controls on visa regulations for Ukraine, would allow illegal immigrants to enter Germany with fake identities.

This proved to be a highly controversial position since Fischer's plan not only clashed with the largely pacifist philosophy of The Greens, but because it also supported for the first time since World War II active participation of German soldiers in combat.

On fundamental issues like the International Criminal Court, the Kyoto Protocol, and the crisis in the Middle East, Fischer was openly differing with the Bush administration.

[20] In 1999, both Fischer and Justice Minister Herta Däubler-Gmelin appealed for clemency for the LaGrand brothers, two German citizens sentenced to death in Arizona.

Fischer has been criticized for attending a 1969 conference of the Palestine Liberation Organization, where Palestinian leader Yasser Arafat called for an all-out war on Israel "until the end".

[25] By 2001, he emerged as a pivotal figure in the hopes for the Israeli–Palestinian peace process, in part because he helped bring about a lull in the violence after the Dolphinarium discotheque massacre in June 2001.

His intervention led to an announced cease-fire arranged by George Tenet, the United States Director of Central Intelligence; Fischer had been in Tel Aviv at the time of the blast.

After the vote, the proposal said, elected officials could continue democratic reforms leading to a provisional Palestinian state by the end of 2003 and to final borders by 2005.

[28] He represented the German government at the funeral services for Arafat on 12 November 2004 in Cairo and at the inauguration of the new Holocaust Memorial Museum at Yad Vashem in March 2005.

[29] In May 2000, Fischer proposed the creation of a European federation with a directly elected president and parliament sharing real executive and legislative powers.

Fischer proposed the eventual enactment of a constitutional treaty that would set out which powers were to be shifted to the new European executive and parliament, and those that remained at national level.

[32] In a paper jointly signed by Fischer and French Foreign Minister Dominique de Villepin, in November 2002, Germany and France pushed for a mutual defence commitment to be part of the constitution.

In 2004, Fischer called on Ukraine to hold a recount of the presidential elections after Putin-backed candidate Viktor Yanukovich was the first to declare his victory despite mass protests in Kyiv.

[35] From September 2006 until 2007, Fischer was a senior fellow at the Liechtenstein Institute on Self-Determination, and as a visiting professor co-taught with Wolfgang F. Danspeckgruber at Woodrow Wilson School of Public and International Affairs, both at Princeton University.

Writing in Der Spiegel, journalist Charles Hawley opined that since 1998, "Joschka Fischer's popularity has been virtually unassailable: The icon of the environmentally minded Green Party could, it seemed, do no wrong.

"[50] As Germany's Foreign Minister, Fischer's popularity soared when he opposed the Iraq War, and his very public struggle with his weight endeared him to many Germans.