Via Lauksargiai (former Laugszargen, Memelland) and a German resettlement camp in Werneck at Würzburg, Van der Bellen’s parents moved to Vienna, where their son Alexander was born in 1944 and baptized into the Lutheran Church. As the Red Army approached Vienna, the family escaped to the Kaunertal in Tyrol, where his father later became active as a businessman again.

In 1954, after completing primary school in Innsbruck, Van der Bellen started attending the Akademisches Gymnasium Innsbruck where he graduated in 1962 with his Matura. Until this time Van der Bellen had Estonian citizenship like his parents, obtaining Austrian citizenship around 1958. According to Van der Bellen himself, he did not complete the mandatory service in the Bundesheer. He underwent a Musterung (military fitness check) twice, the first one resulting in his being rated as unfit (untauglich). However, he successfully passed the second one. Later, he received several respites during his studies and after his marriage. After that Van der Bellen was no long summoned for service, due to his subsequent professorship.

After receiving his Matura Van der Bellen started studying economics at the University of Innsbruck. He completed his studies in 1966 as Diplom-Volkswirt. With his dissertation Kollektive Haushalte und gemeinwirtschaftliche Unternehmungen: Probleme ihrer Koordination (“Collective households and public-service enterprises: Problems of their coordination”) he was awarded the title of Dr. rer. oec (doctor rerum oeconomicarum) in December 1966. From 1968 to 1971 he served as a scientific assistant of Clemens August Andreae at the public finance institution of the University of Innsbruck, and from 1972 to 1974 as research fellow at the international institution for management and administration of the WZB Berlin Social Science Center. He established a friendship with Turkish economist Murat R. Sertel, with who he worked on decision and preference theories and later on published several articles and discussion papers.

In 1976 Van der Bellen was appointed extraordinary university professor at the Innsbruck University, where he remained until 1980. During this time he moved to Vienna to study and research from 1977 to 1980 at the Verwaltungsakademie des Bundes. From 1980 to 1999 he was extraordinary university professor for economics at the University of Vienna. Between 1990 and 1994 he there also became dean of the faculty for economics at University of Vienna. In October 1999 he became parliamentary leader of the Greens in the National Council and thus resigned as university professor in January 2009. Van der Bellen retired in February 2009.

In 1992, Van der Bellen was nominated by the Greens for the office of the President of the Court of Audit; he was defeated by the ÖVP-close Franz Fiedler. After the Greens suffered significant losses in the 1995 legislative elections on 17 December, Van der Bellen took over the party chairmanship from Christoph Chorherr in December 1997 and remained until October 2008, being the longest-serving spokesman in the history of the Austrian Greens, with almost eleven years in office.

With the beginning of the XIX. legislative period on 7 November 1994 Van der Bellen functioned as a member of the National Council for the first time and held this position until 2012. During the XXIV. legislative period he dropped out of the National Council on 5 July 2012. From 1999 to 2008 he was parliamentary leader of the Green Party in the National Council.

He assumed chairmanship with the party having 4.8% approval in polls at that time. He led the party through three elections, each higher than the last: in the 1999 legislative elections the party got 7.4% of the vote, in the 2002 legislative elections it got 9.5% of the vote, and in the 2006 legislative elections the party got 11.05% of the vote. After losses in the 2008 legislative elections, in which the Green Party’s voteshare dropped to 10.11%, Van der Bellen, dubbed “the green professor” by the media, resigned on 3 October 2008 as spokesman of the Green Party. He handed over the office to the Third President of the National Council at the time, Eva Glawischnig. As designated spokesperson she was elected administrative party leader on 24 October and later officially endorsed and sworn in by the party congress (Bundeskongress).

In 2001, Van der Bellen said that he turned from an “arrogant anti-capitalist” into a “broad-minded left-liberal” over the course of his political career. In his 2015 autobiography, Van der Bellen described himself as a liberal positioned in the political centre while downplaying his earlier description as left-liberal, and said he was inspired by the Anglo-Saxon liberal tradition, particularly John Stuart Mill. He is strongly supportive of the European Union, and advocates European federalism. During the 2016 presidential election, he appealed to the political centre and used “Unser Präsident der Mitte” (Our President of the Centre) for his campaign slogan.

After the 2008 legislative elections, he was proposed by the Greens, who were no longer the third strongest party, as a counter-candidate to the controversial FPÖ candidate Martin Graf for the post of Third President of the National Council, however, he failed to win the vote on 28 October 2008: Graf was elected with 109 out of 156 valid votes, Van der Bellen only received 27, and the remaining 20 votes went to other MPs.

At the 2010 Viennese state elections on 10 October Van der Bellen stood as a candidate on the 29th place of the list of the Vienna Greens. With the elections slogan “Go Professor go!” he reached 11,952 preferred votes and thus achieved a precedence on the first place. Although he stated in multiple interviews: “Should I get the preferential votes and it comes to a red-green government, I will definitely move into the Landtag”, he still did not accept the Gemeinderat mandate after the elections and remained in the National Council til 5 July 2012.

On February 2011, Van der Bellen was elected by the red-green city and state government as Commissioner for Universities and Research (also: Commissioner of the City of Vienna for Universities and Research, denotation in 2013). While he himself volunteered this activity, in addition to his still exercised National Council mandate, the new infrastructure office for him with a budget of 210,000 euros annually was endowed.

On 14 June 2012, Van der Bellen announced in a press conference to swap from the National Council to the Vienna Gemeinderat and Landtag. On 5 July 2012 he left the National Council. The inauguration took place in September 2012 at the first Gemeinderat meeting after the summer break. In January 2015, it was announced that Van der Bellen would retreat from Vienna’s municipal politics at the end of the legislative period. In the internal list election of the Vienna Greens on 14 February, after the application deadline, he did not compete in the internal party candidacy. Thus he was no longer on a selectable place on the electoral lists of the Greens in the 2015 Viennese state elections.

Since August 2014 Van der Bellen has already been regarded as a presidential candidate. The Green Party reserved the domain “vdb2016.at” through the media agency Media Brothers for a possible presidential candidacy of Van der Bellen in November 2014. After its reservation the party delegated the domain to the Association “Together for Van der Bellen” as of 6 January 2016.

Van der Bellen married when he was 18 years old and became a father for the first time at 19. His relationship with Brigitte (born Hüttner, 1943–2018) lasted over 50 years, until they divorced in 2015. He had two sons with her. Since December 2015 Van der Bellen has been married to a longtime friend and managing director of the Greens Club, Doris Schmidauer. He lives in Vienna and in Kaunertal, Tyrol.

After Van der Bellen’s victory in the 2016 Austrian presidential elections, President of Estonia Toomas Hendrik Ilves congratulated him. The Estonian Ministry of Foreign Affairs have stated that Van der Bellen could get back his Estonian passport at any time. This is possible because Van der Bellen’s parents were citizens of Estonia as of 16 June 1940; children of such parents are automatically accepted as citizens. Urmas Paet, former foreign minister of Estonia and MEP said: “the election results are a reason to congratulate Austrians twice. For Estonia and its people, the fact that Austria has elected an Estonian citizen as its president also plays a role.”

On 8 January 2016, Van der Bellen officially announced his candidacy for the 2016 presidential election by video message.

In the second round of voting (the runoff election) on 22 May 2016, the provisional final result excluding postal votes was: Norbert Hofer with 51.93% and Alexander Van der Bellen with 48.07%. Therefore no winner could be determined on election night. On the following day (23 May 2016), Interior Minister Wolfgang Sobotka announced the final results including postal votes, according to which Van der Bellen received 50.35% and Hofer 49.64% of valid votes. Van der Bellen had a lead of 31,026 votes on Hofer. The voter turnout was 72.7%.

On 8 June, Freedom Party chairman Heinz-Christian Strache brought in a 150-page notice of appeal to the Constitutional Court, which was intended to highlight deficiencies in the conduct of the second voting round. On 1 July 2016, the Constitutional Court consented the electoral appeal of the Freedom Party. Because of irregularities that occurred in the counting of postal votes, the election had to be repeated in the whole of Austria.

Van der Bellen also won the second runoff election postponed to 4 December 2016, receiving 53.8% of valid votes (with a voter turnout of 74.2%). While Van der Bellen’s lead in the run-off vote on May 2016 amounted to barely less than 31,000 votes, he was able to expand his lead in the second run-off vote on December 2016 to over 348,000 valid votes.

Alexander Van der Bellen was inaugurated as President of Austria on 26 January 2017. After his inaugural speech he met with the Kern government and was greeted with a military ceremony as the new commander-in-chief of the Bundesheer.

As a young man Van der Bellen left the Evangelical Church, because he was upset about his local pastor. According to his own words he does not believe in the one God, but in a “message or vision” (“Botschaft oder Vision”), which in his view the New Testament states. However, in an interview in 2019 he stated, that he re-joined the Evangelical Church of the Augsburg Confession the same year.