He also served as Federal Commissioner from 1990 to 2000, earning recognition as a "Stasi hunter" and "tireless pro-democracy advocate" for exposing the crimes of the communist secret police.

A son of a survivor of a Soviet Gulag,[13][14][15][16][17] Gauck's political life was formed by his own family's experiences with totalitarianism.

[22] The Wall Street Journal has described him as "the last of a breed: the leaders of protest movements behind the Iron Curtain who went on to lead their countries after 1989".

In 2022, he criticized Germany's policies towards Russia in the period after the Cold War, and said that "we should have listened to the voices of our eastern neighbours – Poles and the Baltic states as well as our Atlantic friends" when they warned about Russian aggression.

[26] He was convicted by a Russian military tribunal of espionage for receiving a letter from the West and also of anti-Soviet demagogy for being in the possession of a western journal on naval affairs, and deported to a Gulag in Siberia,[27] where he was mistreated to the extent that he was considered physically disabled after one year, according to his son.

According to Gauck, his political activities were inspired by the ordeal of his father,[30] and he stated that he grew up with a "well-founded anti-communism".

His work as a pastor in East Germany was very difficult due to the hostility of the Communist regime towards the church, and for many years he was under constant observation and was harassed by the Stasi (the secret police).

On 2 October 1990, the day before the dissolution of the GDR, the People's Chamber elected him Special Representative for the Stasi Records.

After the dissolution of the GDR the following day, he was appointed Special Representative of the Federal Government for the Stasi Records by President Richard von Weizsäcker and Chancellor Helmut Kohl.

The 1990 People's Chamber was granted the right to nominate a certain number of MPs as part of the reunification process and he was one of the 144 Volkskammer co-opted to the Bundestag.

Gauck refused the position of president of the Federal Agency for Civic Education as well as offers to be nominated as a candidate for parliament by the SPD.

[38] Since 2003, Gauck has been chairman of the association Gegen Vergessen – Für Demokratie ("Against Forgetting – For Democracy"), and he served on the Management Board of the European Monitoring Centre on Racism and Xenophobia 2001–2004.

In 2007, Gauck was invited to deliver the main speech during a commemoration ceremony at the Landtag of Saxony in memory of the reunification of Germany and the fall of the Communist government.

[40] All parties participated, except The Left (the successor of SED), whose members walked out in protest against Gauck's delivering the speech.

[48] The Wall Street Journal has described him as "the last of a breed: the leaders of protest movements behind the Iron Curtain who went on to lead their countries after 1989", comparing him to Lech Wałęsa and Václav Havel.

[51] In an interview with Radio Free Europe/Radio Liberty in 2007, Gauck said that "we have to delegitimatize [the Communist era] not only because of the many victims and criminal acts, but [also because] modern politics in the entire Soviet empire was basically taken backward.

[52] In May 2015, Gauck urged Germans to openly acknowledge that "millions of soldiers of the Red Army lost their lives during Nazi internment.

"[53] In 2022, Gauck criticized Germany's policies towards Russia in the period after the Cold War, and said that "we should have listened to the voices of our eastern neighbours – Poles and the Baltic states as well as our Atlantic friends" when they warned about Russian aggression.

[60] His main contender, Christian Wulff, and politicians of all the government parties, stated that they greatly respected Gauck and his life and work.

[63] CSU politician Philipp Freiherr von Brandenstein argued that the election of Gauck would prevent any cooperation between SPD/Greens and Die Linke for years to come, saying that "Gauck has likely made it perfectly clear to [Sigmar] Gabriel that he will never appoint any of the apologists of the Communist tyranny as government members.

[65][66] Die Linke's refusal to support Gauck drew strong criticism from the SPD and Greens.

[67][68] Gabriel, the SPD chairman, described Die Linke's position as "bizarre and embarrassing", stating that he was "shocked" that the party would declare Gauck their main enemy due to his investigation of Communist injustice.

[80] Gabriel stated that the reason that Die Linke was the only party that did not support Gauck was its "sympathy for the German Democratic Republic".

[87] The new president took the oath of office required by article 56 of Germany's Constitution on 23 March 2012 in the presence of the assembled members of the Bundestag and the Bundesrat.

On 18 September 2014, Gauck welcomed the heads of states of partly German-speaking countries, such as Austria, Switzerland, Belgium, Luxembourg, and Liechtenstein, to his home region of Mecklenburg.

[100] His son Christian, who along with his brother decided to leave the GDR in early 1984 and was able to do so in 1987, studied medicine in West Germany and became a physician.